IP tunnels
IP tunnels overview
This section discusses IP Security (IPsec), GRE tunneling, and IP-IP tunneling features supported by the MS-ISA2/ESA-VM (ISA is used to refer to any of these hardware). In these applications, the ISA functions as a resource module for the system, providing encapsulation and (for IPsec) encryption functions. The IPsec encryption functions provided by the ISA are applicable for many applications including mobile backhaul, encrypted SDPs, video wholesale, site-to-site encrypted tunnel, and remote access VPN concentration.
7750 SR IPsec implementation architecture shows an example of an IPsec deployment, and the way this would be supported inside a 7750 SR. GRE and IP-IP tunnel deployments are very similar. IP tunnels have two flavors GRE/IP-IP, in all but a few areas the information for IP tunnels applies to both types.
7750 SR IPsec implementation architecture, the public network is typically an ‟insecure network” (for example, the public Internet) over which packets belonging to the private network in the diagram cannot be transmitted natively. Inside the 7750 SR, a public service instance (IES or VPRN) connects to the public network and a private service instance (typically a VPRN) connects to the private network.
The public and private services are typically two different services, and the ISA is the only ‟bridge” between the two. Traffic from the public network may need to be authenticated and encrypted inside an IPsec tunnel to reach the private network. In this way, the authenticity/confidentiality/integrity of accessing the private network can be enforced. If authentication and confidentiality are not important then access to the private network may alternatively be provided through GRE or IP-IP tunnels.
The ISA provides a variety of encryption features required to establish bidirectional IPsec tunnels including:
control plane
manual keying
dynamic keying: IKEv1/v2
IKEv1 mode: main and aggressive
authentication: Pre-Shared-Key /xauth with RADIUS support/X.509v3 Certificate/EAP
Perfect Forward Secrecy (PFS)
DPD
NAT-Traversal
security policy
DH-Group: 1/2/5/14/15/19/20/21
data plane
ESP (with authentication) tunnel mode
authentication algorithm: MD5/SHA1/SHA256/SHA384/SHA512/AES-XCBC
encryption algorithm: DES/3DES/AES128/AES192/AES256/AES-GCM128/AES-GCM192/AES-GCM256/AES-GMAC128/AES-GMAC192/AES-GMAC256
anti-replay protection
N:M IPsec ISA card redundancy
SR OS uses a configured authentication algorithm for the Pseudorandom Function (PRF). IPsec features are supported on the 7750 SR, the 7450 ESS, and VSR.
There are two types of tunnel interfaces and SAPs. See Tunnel interfaces and SAPs for more information.
Tunnel interface/SAP | Association/configuration |
---|---|
Public tunnel interface |
configured in the public service; outgoing tunnel packets have a source IP address in this subnet |
Public tunnel SAP |
associated with the public tunnel interface; a logical access point to the ISA card in the public service |
Private tunnel interface |
configured in the private service; can be used to define the subnet for remote access IPsec clients |
Private tunnel SAP |
associated with the private tunnel interface, a logical access point to the ISA card in the private service |
Traffic flows to and through the ISA card as follows:
upstream direction
The encapsulated (and possibly encrypted) traffic is forwarded to a public tunnel interface if its destination address matches the local or gateway address of an IPsec tunnel or the source address of a GRE or IP-IP tunnel. Inside the ISA card, encrypted traffic is decrypted, the tunnel header is removed, the payload IP packet is delivered to the private service, and from there, the traffic is forwarded again based on the destination address of the payload IP packet.
downstream direction
Unencapsulated/clear traffic belonging to the private service is forwarded into the tunnel by matching a route with the IPsec/GRE/IP-IP tunnel as next-hop. The route can be configured statically, learned by running OSPF on the private tunnel interface (GRE tunnels only), learned by running BGP over the tunnel (IPsec and GRE tunnels only), or learned dynamically during IKE negotiation (IPsec only). After clear traffic is forwarded to the ISA card, it is encrypted if required, encapsulated per the tunnel type, delivered to the public service, and from there, the traffic is forwarded again based on the destination address of the tunnel header.
Tunnel ISAs
A tunnel group is a collection of MS-ISA2s (MDA type isa2-tunnel) or ESA-VM (VM type tunnel) configured to handle the termination of one or more IPsec, GRE, or IP-IP tunnels.
The following example displays tunnel group configurations.
MD-CLI
[ex:/configure isa]
A:admin@node-2# info
tunnel-group 1 {
admin-state enable
isa-scale-mode tunnel-limit-2k
primary 1/1
backup 2/1
}
tunnel-group 2 {
admin-state enable
multi-active {
isa 3/1 { }
isa 3/2 { }
}
tunnel-group 3 {
admin-state enable
multi-active {
esa 3 vm 1 { }
esa 4 vm 1 { }
}
classic CLI
A:node-2>config>isa# info
----------------------------------------------
tunnel-group 1 isa-scale-mode tunnel-limit-2k create
primary 1/1
backup 1/2
no shutdown
exit
tunnel-group 2 isa-scale-mode tunnel-limit-2k create
multi-active
mda 3/1
mda 3/2
no shutdown
exit
tunnel-group 3 create
multi-active
esa-vm 3/1
esa-vm 4/1
no shutdown
exit
A GRE, IP-IP, or IPsec tunnel belongs to only one tunnel group. There are two types of tunnel groups:
-
single-active tunnel group
A single-active tunnel group can have one tunnel-ISA designated as primary and, optionally, one other tunnel-ISA designated as backup. If the primary ISA fails the affected failed tunnels are re-established on the backup (which is effectively a cold standby) if it is not already in use as a backup for another tunnel group.
-
multi-active tunnel group
A multi-active tunnel group can have multiple tunnel-ISAs designated as primary. Only one ISA is supported on VSR.
A multi-active tunnel is the recommended tunnel group type. Certain features like MC-IPsec are only supported with a multi-active tunnel group.
The ESA-VM is only supported in a multi-active tunnel group.
Note that the ESA-VM and ISA/ISA2 cannot coexist in the same tunnel group.
The show isa tunnel-group command allows the user to view information about all configured tunnel groups. This command displays the following information for each tunnel group: group ID, primary tunnel-ISAs, backup tunnel-ISAs, active tunnel-ISAs, administrative state, and operational state.
There are three thresholds that are used to monitor memory usage in a tunnel-ISA:
-
max-threshold
When the memory usage of an ISA exceeds this threshold, any new IKE states are rejected.
-
high-watermark
When the memory usage of an ISA exceed this threshold, a trap is generated.
-
low-watermark
When the memory usage of an ISA fall below this threshold, a clear trap is generated.
These three thresholds are fixed, not configurable.
A tunnel-group has an isa-scale-mode, which defines the maximum number of all tunnels (all types combined) which can be established on each ISA of the tunnel group. The available tunnel limits vary per platform.
Public tunnel SAPs
A VPRN or IES service (the delivery service) must have at least one IP interface associated with a public tunnel SAP to receive and process the following types of packets associated with GRE, IP-IP, and IPsec tunnels:
-
GRE (IP protocol 47)
-
IP-IP (IP protocol 4)
-
IPsec ESP (IP protocol 50)
-
IKE (UDP)
The public tunnel SAP type has the format tunnel-tunnel-group.public:index, as shown in the following CLI example.
MD-CLI
[ex:/configure service]
A:admin@node-2# info
ies "1" {
admin-state enable
customer "1"
interface "public" {
tos-marking-state untrusted
sap tunnel-1.public:200 {
}
ipv4 {
primary {
address 192.168.12.1
prefix-length 24
}
}
}
}
vprn "2" {
customer "1"
bgp-ipvpn {
mpls {
admin-state enable
route-distinguisher "10.1.1.1:65007"
}
}
interface "greTunnel" {
tunnel true
ipv4 {
addresses {
address 10.0.0.1 {
prefix-length 24
}
}
dhcp {
admin-state enable
}
}
sap tunnel-1.private:210 {
ip-tunnel "toCel" {
admin-state enable
delivery-service "service1"
remote-ip-address 10.251.12.2
backup-remote-ip-address 10.251.12.22
local-ip-address 192.168.12.100
gre-header {
admin-state enable
}
dest-ip 10.0.0.2 { }
}
}
}
}
classic CLI
A:node-2>config>service# info
----------------------------------------------
customer 1 create
description "Default customer"
exit
ies 1 customer 1 create
interface "public" create
address 192.168.12.1/24
tos-marking-state untrusted
sap tunnel-1.public:200 create
exit
exit
no shutdown
exit
vprn 2 customer 1 create
interface "greTunnel" tunnel create
address 10.0.0.1/24
dhcp
no shutdown
exit
sap tunnel-1.private:210 create
ip-tunnel "toCel" create
dest-ip 10.0.0.2
gre-header
source 192.168.12.100
remote-ip 10.251.12.2
backup-remote-ip 10.251.12.22
delivery-service 1
no shutdown
exit
exit
exit
bgp-ipvpn
mpls
route-distinguisher 10.1.1.1:65007
no shutdown
exit
no shutdown
exit
Private tunnel SAPs
The private service must have an IP interface to a GRE, IP-IP, or IPsec tunnel to forward IP packets into the tunnel, causing them to be encapsulated (and possibly encrypted) per the tunnel configuration and to receive IP packets from the tunnel after the encapsulation has been removed (and decryption). That IP interface is associated with a private tunnel SAP.
The private tunnel SAP has the format tunnel-tunnel-group.private:index, as shown in the following CLI example where a GRE tunnel is configured under the SAP.
Use the following command to see information about an IP tunnel.
show ip tunnel
===============================================================================
IP Tunnels
===============================================================================
TunnelName SapId SvcId Admn
Local Address DlvrySvcId Oper
OperRemoteAddress
-------------------------------------------------------------------------------
tun-1-gre-tunnel tunnel-1.private:1 201 Up
192.168.1.2 1201 Up
192.168.3.2
-------------------------------------------------------------------------------
IP Tunnels: 1
===============================================================================
IP interface configuration
In the configuration example of the previous section the IP address 10.0.0.1 is the address of the GRE tunnel endpoint from the perspective of payload IP packets. This address belongs to the address space of the VPRN 1 service and is not exposed to the public IP network carrying the GRE encapsulated packets. An IP interface associated with a private tunnel SAP does not support unnumbered operation.
It is possible to configure the IP MTU (M) of a private tunnel SAP interface. This sets the maximum payload IP packet size (including IP header) that can be sent into the tunnel, for example, it applies to the packet size before the tunnel encapsulation is added. When a payload IPv4 packet that needs to be forwarded into the tunnel is larger than M bytes the payload packet is IP fragmented (before tunnel encapsulation) if the DF bit is clear, otherwise the packet is discarded. When a payload IPv6 packet that needs to be forwarded into the tunnel is larger than M bytes the packet is discarded if its size is less than 1280 bytes otherwise it is forwarded and encapsulated intact.
GRE and IP-IP tunnel configuration
To bind an IP/GRE or IP-IP tunnel to a private tunnel SAP, an IP tunnel should be created under the SAP.
To configure the tunnel as an IP/GRE tunnel, the gre-header command must be present in the configuration of the IP tunnel. To configure the tunnel as an IP-IP tunnel, the GRE header should be disabled in the IP tunnel configuration.
When configuring a GRE or IP-IP tunnel, the dest-ip command specifies an IPv4 or IPv6 address (private) of the remote tunnel endpoint. A tunnel can have up to 16 dest-ip addresses. If any of the dest-ip addresses are not contained by a subnet of the local private endpoint, the tunnel does not come up. In the ip-tunnel context, there are commands to configure the following:
-
source address of the GRE or IP-IP tunnel
This is the source IPv4 address of GRE or IP-IP encapsulated packets sent by the delivery service. It must be an address in the subnet of the associated public tunnel SAP interface.
-
remote IP address
If this address is reachable in the delivery service (there is a route), this is the destination IPv4 address of GRE or IP-IP encapsulated packets sent by the delivery service.
-
backup remote IP address
If the remote IP address of the tunnel is not reachable, this is the destination IPv4 address of GRE or IP-IP encapsulated packets sent by the delivery service.
-
delivery service
This is the ID or name of the IES or VPRN service where GRE or IP-IP encapsulated packets are injected and terminated. The delivery service can be the same service where the private tunnel SAP interface resides.
-
DSCP marking in the outer IP header of GRE encapsulated packets
If this is not configured, the default is to copy the DSCP from the inner IP header to the outer IP header.
A private tunnel SAP can have only one IP tunnel sub-object (one GRE or IP-IP tunnel per SAP).
The show ip tunnel command displays information about a specific IP tunnel or all configured IP tunnels. The following information is provided for each tunnel:
-
service ID that owns the tunnel
-
private tunnel SAP that owns the tunnel
-
tunnel name, source address
-
remote IP address
-
backup remote IP address
-
local (private) address
-
destination (private) address
-
delivery service
-
dscp
-
admin state
-
oper state
-
type (GRE or IP-IP)
Use the following command to display information about a specific IP tunnel.
show ip tunnel tunnel-name
===============================================================================
IP Tunnel Configuration Detail
===============================================================================
Service Id : 1 Sap Id : tunnel-1.private:1
Tunnel Name : ipv6-gre
Description : None
GRE Header : Yes Delivery Service : 2
GRE Keys Set : False
GRE Send Key : N/A GRE Receive Key : N/A
Admin State : Up Oper State : Up
Source Address : 2001:db8::1:2:3:4
Remote Address : 3ffe:1::2
Backup Address : (Not Specified)
Oper Remote Addr : 3ffe:1::2
DSCP : ef
Reassembly : inherit
Clear DF Bit : false IP MTU : max
Encap IP MTU : 1400
Pkt Too Big : true
Pkt Too Big Numb*: 100 Pkt Too Big Intvl: 10 secs
Oper Flags : None
Last Oper Changed: 02/09/2015 15:22:38
Host MDA : 1/2
-------------------------------------------------------------------------------
Target Address Table
-------------------------------------------------------------------------------
Destination IP IP Resolved Status
-------------------------------------------------------------------------------
172.16.1.2 Yes
2001:db8::2 Yes
-------------------------------------------------------------------------------
===============================================================================
IP Tunnel Statistics: ipv6-gre
===============================================================================
Errors Rx : 0 Errors Tx : 0
Pkts Rx : 0 Pkts Tx : 0
Bytes Rx : 0 Bytes Tx : 0
Key Ignored Rx : 0 Too Big Tx : 0
Seq Ignored Rx : 0
Vers Unsup. Rx : 0
Invalid Chksum Rx: 0
Key Mismatch Rx : 0
===============================================================================
===============================================================================
Fragmentation Statistics
===============================================================================
Encapsulation Overhead : 44
Pre-Encapsulation
Fragmentation Count : 0
Last Fragmented Packet Size : 0
Post-Encapsulation
Fragmentation Count : 0
Last Fragmented Packet Size : 0
===============================================================================
===============================================================================
IP fragmentation and reassembly for IP tunnels
An IPsec, GRE, or IP-IP tunnel packet that is larger than the IP MTU of some interface in the public network must either be discarded (if the Do Not Fragment (DF) bit is set in the outer IP header) or fragmented. If the tunnel packet is fragmented, then it is up to the destination tunnel endpoint to reassemble the tunnel packet from its fragments. IP reassembly can be enabled for all the IPsec, GRE, and IP-IP tunnels belonging to a tunnel group. For IP-IP and GRE tunnels, the reassembly option is also configurable on a per-tunnel basis so that some tunnels in the tunnel group can have reassembly enabled, and others can have the extra processing disabled. When reassembly is disabled for a tunnel, all received fragments belonging to the tunnel are dropped.
To avoid public network fragmentation of IPsec, GRE, or IP-IP packets belonging to a particular tunnel, one possible strategy is to fragment IPv4 payload packets larger than a specified size M at entry into the tunnel (before encapsulation and encryption if applicable). The size M is configurable using the ip-mtu command under the template, service, or router IPsec tunnel contexts.
If the payload IPv4 packets are all M bytes or less in length then it is guaranteed that all resulting tunnel packets are less than M+N bytes in length, if N is the maximum overhead added by the tunneling protocol. If M+N is less than the smallest interface IP MTU in the public network, fragmentation is avoided. In some cases, some of the IPv4 payload packets entering a tunnel may have their DF bit set. And if needed, the SR OS supports the option (also configurable on a per-tunnel basis) to clear the DF bit in these packets so that they can be fragmented.
The system allows users to configure an encapsulated-ip-mtu for a tunnel in the template, service, or router IPsec tunnel contexts. This represents the maximum size of the encapsulated tunnel packet. After encapsulation, If the IPv4 or IPv6 tunnel packet size exceeds the configured encapsulated-ip-mtu, the system fragments the packet against the encapsulated-ip-mtu.
The following is a description of system behavior about fragmentation:
-
private side
If the size, before encapsulation, of the IPv4 or IPv6 packet entering the tunnel is larger than the IP MTU configured for the template, service, or router IPsec tunnel:
-
IPv4 payload packet
If the DF bit is not set in the packet or if the clear-df-bit command is configured, the system fragments the packet against the IP MTU configured in the template, service, or router IPsec tunnel context.
Otherwise, the system drops the packet and sends back an ICMP error Fragmentation required and DF flag set, with the suggested MTU set as the IP MTU.
-
IPv6 payload packet
If the packet size >1280 bytes, the system drops the packet and sends back an ICMPv6 Packet Too Big (PTB) message with the suggested MTU set as the IP MTU.
If the packet size<=1280 bytes, the system forwards the packet into the tunnel.
-
-
public side
This applies to both ESP and IKE packets, IPv4 and IPv6.
If the ESP/IKE packet is larger than the encapsulated-ip-mtu, the system fragments the packet against the encapsulated-ip-mtu; however, when the IPv6 ESP/IKE packet is smaller than 1280 bytes, the system does not fragment it, even if it is larger than the encapsulated-ip-mtu.
TCP MSS adjustment
The system supports the Transmission Control Protocol (TCP) Maximum Segment Size (MSS) adjustment feature for the following types of tunnels on the ISA:
IPsec
-
IPinIP/GRE
-
L2TPv3 (data packet only)
The intent of TCP MSS adjustment is to avoid IP-level fragmentation for TCP traffic encapsulated in a tunnel by updating the MSS option value in the TCP SYN packet with an appropriate value. This feature is useful when there is tunnel encapsulation that is not known by a TCP host, and the extra tunnel encapsulation overhead may cause IP-level fragmentation.
The system supports TCP MSS adjustment on both the public and private sides.
On the public side, when the ISA receives a tunnel packet (such as ESP), after decryption or decapsulation, if the payload packet is a TCP SYN packet, then the ISA replaces the MSS option with a configured value if the configured MSS value is smaller than the received MSS value or when there is no MSS option:
-
If public-tcp-mss-adjust auto is configured, then:
new MSS value =public_side_MTU – tunnel_overhead – TCP fixed header – IP fixed header
where:
-
public_side_MTU = encapsulated-ip-mtu
If encapsulated-ip-mtu is not configured, which means there is no post-encap fragmentation on ISA, then TCP MSS adjust is disabled.
-
TCP fixed header = 20
-
IP fixed header = 20 (Ipv4) or 40 (IPv6)
-
-
If a specific MSS value for the public-tcp-mss-adjust is configured, the new MSS value is set to the public-tcp-mss-adjust value.
-
The public-tcp-mss-adjust auto command only applies to IPsec and IPinIP/GRE tunnels.
-
For an IPsec tunnel, the tunnel_overhead is the maximum overhead of the corresponding CHILD_SA.
-
For an IPinIP tunnel, the tunnel_overhead is 0.
-
For a GRE tunnel, the tunnel_overhead is length of GRE header.
The private side is similar to the public side. The system processes the received TCP SYN packet on the private side if the TCP MSS adjust is enabled. However, there is no auto parameter for private-tcp-mss-adjust command.
MTU propagation
MTU propagation is an optional feature that allows the system to listen for fragmentation-related ICMP error message received from the public side of the tunnel. These error messages include:
ICMP Destination Unreachable message "fragmentation needed and DF set" (type 3, code 4)
ICMPv6 Packet Too Big message (type 2)
The suggested MTU value in the ICMP message is used to derive two MTU values:
Temporary public MTU (TMTU) are determined as follows:
The TMTU starts with a configured encapsulated-ip-mtu value.
If the received MTU is less than 1280 and it is from an ICMPv6 packet, the received value is ignored.
If the received MTU is less than 512 and it is from an ICMP packet, the received value is ignored.
If the received MTU is greater than or equal to the configured encapsulated-ip-mtu value, the received value is ignored.
If the received MTU is greater than or equal to the current TMTU, the received value is ignored.
If the received MTU is less than the current TMTU, it replaces the current TMTU.
To prevent attack and rapid change, there is a damp time of 60 seconds after a new TMTU value is set. Within that time frame, all received MTU values are ignored.
TMTU has a lifetime timer (configurable with an aging interval). When the lifetime timer expires, the TMTU’s value is reset to the encapsulated-ip-mtu value. The lifetime timer resets whenever a new TMTU value is set.
TMTU is a per tunnel value.
Temporary private MTU (TPMTU) equals TMTU – Tunnel_Encap_Overhead.
TPMTU is a per CHILD_SA value.
-
Tunnel_Encap_Overhead is a fixed value for a non-IPsec tunnel-per-tunnel type. For an IPsec tunnel, its value is the maximum overhead based on the value used by the CHILD_SA set using the following command:
- MD-CLI
configure ipsec ipsec-transform id
- classic
CLI
configure ipsec ipsec-transform
- MD-CLI
TMTU and TPMTU are used in the following cases:
TPMTU is used for fragmenting IP packets received on the private side instead of the configured IP MTU.
IKEv2 message fragmentation uses TMTU instead of the configured encapsulated-ip-mtu.
IKE IP packet fragmentation uses TMTU instead of the configured encapsulated-ip-mtu.
To derive the TCP MSS value for the TCP MSS adjustment, instead of configured encapsulated-ip-mtu.
ESP packet fragmentation (post-encapsulation fragmentation) does not use TMTU; it only uses the configured encapsulated-ip-mtu value.
To enable this feature, configure the propagate-pmtu-v4 and propagate-pmtu-v6 commands in the template, service, or router IPsec tunnel contexts.
Load-balancing IP tunnels
A specific IP tunnel is assigned to only one ISA or ESA-VM. In a multi-active tunnel group, the IP tunnels are spread across all active ISAs or ESA-VMs by hashing their source and destination IP address in the tunnel header. By default, all ISA or ESA-VM are considered equally when the system assigns a tunnel to an ISA or ESA-VM.
In the case of ESA-VMs, because there are different ESA models, each ESA-VM can be configured differently in terms of CPU cores and memory capacity. For a tunnel group containing ESA-VMs with different capacities, users can configure a weight for each VM, such that the VMs with larger weight are assigned more tunnels. For an N:M designated-standby tunnel group, users can configure the weight for the ESA-VMs under the tunnel member pool. See N:M MC-IPsec redundancy for information about N:M redundancy.
Use the following commands to configure the ESA-VM weight:
- MD-CLI
configure isa tunnel-group multi-active esa weight configure isa tunnel-member-pool esa weight
- classic
CLI
configure isa tunnel-group esa-vm configure isa tunnel-member-pool esa-vm
The supported weight value range is 1 to 1000. The configured weight is normalized to a number of hash slots, which ranges from 1 to 32 slots (or 1 to 16 slots if the ESA hosting card is an FP3 card). Additional tunnels are assigned to the VM with more hash slots.
If an active ESA-VM fails, the system replaces it with a standby VM of the same weight. However, if there is no such standby VM, the system removes all tunnels of the tunnel group. If multichassis redundancy is enabled for the tunnel group, the system reboots all active VMs.
Use the following commands to display information about the configured weights and normalized hash slots for a tunnel group or tunnel member pool.
show isa tunnel-group detail
show isa tunnel-member-pool detail
IPsec tunnel types
- LAN-to-LAN tunnel (L2L):
- static LAN-to-LAN (SL2L)
- dynamic LAN-to-LAN (DL2L)
- remote-access tunnel (RA)
The following features and restrictions apply to SL2L tunnels:
- Per-tunnel configuration is supported, which allows each tunnel to be explicitly configured.
- Each tunnel can be used as the next hop in static routes (directly) or BGP (indirectly).
- SL2L tunnels can act as either the tunnel initiator or responder.
- SL2L tunnels support PSK or certificate-based authentication (or PSK only, in the case of IKEv1).
DL2L tunnels are also used for LAN interconnection. Typically, they are used in a hub-spoke topology where a DL2L tunnel is used on the hub site and the SL2L tunnels are used on the spoke sites. The following figure shows a DL2L tunnel in a hub-spoke topology.
The following features and restrictions apply to DL2L tunnels:
- Per-tunnel configuration is not supported; configuration is per-IPsec gateway only.
- A DL2L tunnel is created dynamically when the IPsec gateway receives an incoming tunnel creation request.
- Reverse routes are created dynamically in a private VRF based on the negotiated TSi to route clear traffic into the tunnel.
- DL2L tunnels can only act as the tunnel responder.
- DL2L tunnels support PSK or certificate-based authentication (or PSK only, in the case of IKEv1)
RA tunnels are typically used by end-user devices to securely access the private network, for example, in the road-warrior VPN use case. The following figure shows an RA tunnel used to access a private network.
The following features and restrictions apply to RA tunnels:
- Similar to DL2L, configuration for RA tunnels is per-IPsec gateway only.
- An RA tunnel is created dynamically upon receiving a tunnel creation request from the IPsec client.
- The RA tunnel client requests an internal IP address assignment from the SeGW during tunnel creation. These addresses are used as the source address of the private traffic sent by client. Other optional information, such as the DNS server address, can also be returned by the SeGW.
- RA tunnels support the following authentication options:
- PSK (optionally with RADIUS)
- certificate-based authentication (optionally with RADIUS)
- EAP with RADIUS
-
RA tunnels support optional RADIUS accounting
Operational conditions
A tunnel group that is in use cannot be deleted. In single-active mode, changes to the primary ISA are allowed only when the tunnel group is in a shutdown state. Changing the configured backup ISA (or adding a backup ISA) is allowed at any time unless the ISA is currently active for this tunnel group. When the backup ISA is active, changing the primary ISA is allowed without shutting down the tunnel group.
Changes can be made to the following:
-
the mode from multi-active to single-active
-
the primary ISA that is in single-active mode
-
the active MDA number value that is in multi-active mode
-
enabling or disabling the following configuration
configure isa tunnel-group ipsec-responder-only
In multi-active mode, if the active member ISA goes down, the system replaces it with a backup ISA. However, if a backup ISA is not available, the tunnel group is placed in an operationally down state. A multi-active tunnel group with MC-IPsec enabled cannot be changed into single active-mode unless it is first removed from the MC-IPsec configuration.
The public interface address can be changed at any time; however, if changed, any static tunnels that were configured to use the public interface address require a configuration changes accordingly. Otherwise, the tunnels are in an operationally down state until their configuration is corrected. The public service cannot be deleted while tunnels are associated.
A tunnel group ID or tag cannot be changed. To remove a tunnel-group instance, it must be in a shutdown state and all IPsec tunnels and IPsec gateways that terminated on the tunnel group must be removed first.
The security policy cannot be changed while an IPsec tunnel is administratively up and using the security policy.
The tunnel local gateway address, peer address, local ID, and public or private service ID parameters cannot be changed while the IPsec gateway or IPsec tunnel is administratively up.
Each IPsec gateway or IPsec tunnel has an administrative state. When the administrative state is down, tunnels cannot be set up.
Each IPsec gateway and IPsec tunnel has an operation state. The operational state can have three possible values:
-
oper-up
All configuration and related information are valid and fully ready for tunnel setup.
-
oper-down
Some critical configuration information is missing or not ready. Tunnels cannot be set up.
-
limited
Not all configuration information is ready to become fully operationally up. When IPsec gateway is in a limited state, it is possible that a new tunnel cannot be established. When the IPsec tunnel is in a limited state, reconnection may fail.
When an IPsec gateway or IPsec tunnel transitions from operationally up to an operationally limited state directly as a result of a hot (non-service affecting) configuration change, established tunnels are not impacted. However, if the IPsec gateway or IPsec tunnel transitions to an operationally down state before it is operationally limited as a result of a service-affecting configuration change, then established tunnels are removed. All operational state transitions are logged.
IPsec gateways or IPsec tunnels can enter the limited state because of the following reasons, among others:
-
A Certificate Authority (CA) profile in the configured trust-anchor-profile goes down after the IPsec gateway or IPsec tunnel becomes operationally up.
-
An entry in a configured certificate profile goes down after the IPsec gateway or IPsec tunnel becomes operationally up.
Dynamic configuration change support for IPsec gateway
All dynamic IPsec tunnels (dynamic LAN-to-LAN tunnels and remote-access tunnels) that terminate on the same IPsec gateway share the same configuration. Use the respective commands in the following contexts to configure an IPsec gateway for an IES or VPRN service:
-
MD-CLI
configure service ies interface sap ipsec-gateway configure service vprn interface sap ipsec-gateway
-
classic CLI
configure service ies interface sap ipsec-gw configure service vprn interface sap ipsec-gw
SR OS provides dynamic configuration change capability to modify specific IPsec gateway configurations without impacting existing tunnels.
The following IPsec gateway configurations are dynamically configurable without shutting down the IPsec gateway:
Changing the pre-shared key, using the following commands:
-
MD-CLI
configure service ies interface sap ipsec-gateway pre-shared-key configure service vprn interface sap ipsec-gateway pre-shared-key
-
classic CLI
configure service ies interface sap ipsec-gw pre-shared-key configure service vprn interface sap ipsec-gw pre-shared-key
-
Changing the reference of the IKE policy, using the following commands:
-
MD-CLI
configure service ies interface sap ipsec-gateway ike-policy configure service vprn interface sap ipsec-gateway ike-policy
-
classic CLI
configure service ies interface sap ipsec-gw ike-policy configure service vprn interface sap ipsec-gw ike-policy
-
Changing the reference of the tunnel template, using the following commands:
-
MD-CLI
configure service ies interface sap ipsec-gateway default-tunnel-template configure service vprn interface sap ipsec-gateway default-tunnel-template
-
classic CLI
configure service ies interface sap ipsec-gw default-tunnel-template configure service vprn interface sap ipsec-gw default-tunnel-template
-
Enabling or changing reference of the RADIUS authentication policy, using the following commands:
-
MD-CLI
configure service ies interface sap ipsec-gateway radius authentication-policy configure service vprn interface sap ipsec-gateway radius authentication-policy
-
classic CLI
configure service ies interface sap ipsec-gw radius-authentication-policy configure service vprn interface sap ipsec-gw radius-authentication-policy
-
Enabling or changing the reference of the RADIUS accounting policy, using the following commands:
-
MD-CLI
configure service ies interface sap ipsec-gateway radius accounting-policy configure service vprn interface sap ipsec-gateway radius accounting-policy
-
classic CLI
configure service ies interface sap ipsec-gw radius-accounting-policy configure service vprn interface sap ipsec-gw radius-accounting-policy
-
Enabling, disabling, or changing reference of the TS negotiation, using the following commands:
-
MD-CLI
configure service ies interface sap ipsec-gateway ts-list configure service vprn interface sap ipsec-gateway ts-list
-
classic CLI
configure service ies interface sap ipsec-gw ts-negotiation configure service vprn interface sap ipsec-gw ts-negotiation
-
Enabling, disabling, or changing reference of the client database, using the command options in the following contexts:
-
MD-CLI
configure service ies interface sap ipsec-gateway client-db configure service vprn interface sap ipsec-gateway client-db
-
classic CLI
configure service ies interface sap ipsec-gw client-db configure service vprn interface sap ipsec-gw client-db
-
Changing the certificate configuration, using the commands in the following contexts:
-
MD-CLI
configure service ies interface sap ipsec-gateway cert configure service vprn interface sap ipsec-gateway cert
-
classic CLI
configure service ies interface sap ipsec-gw cert configure service vprn interface sap ipsec-gw cert
-
Changing DHCPv4-based address assignments, using the commands in the following contexts:
-
MD-CLI
configure service ies interface sap ipsec-gateway dhcp-address-assignment dhcpv4 configure service vprn interface sap ipsec-gateway dhcp-address-assignment dhcpv4
-
classic CLI
configure service ies interface sap ipsec-gw dhcp configure service vprn interface sap ipsec-gw dhcp
-
Changing DHCPv6-based address assignments, using the commands in the following contexts:
-
MD-CLI
configure service ies interface sap ipsec-gateway dhcp-address-assignment dhcpv6 configure service vprn interface sap ipsec-gateway dhcp-address-assignment dhcpv6
-
classic CLI
configure service ies interface sap ipsec-gw dhcp6 configure service vprn interface sap ipsec-gw dhcp6
-
Changing local address assignment configuration, using the commands in the following contexts:
-
MD-CLI
configure service ies interface sap ipsec-gateway local address-assignment configure service vprn interface sap ipsec-gateway local address-assignment
-
classic CLI
configure service ies interface sap ipsec-gw local-address-assignment configure service vprn interface sap ipsec-gw local-address-assignment
-
Existing tunnels are not impacted by dynamic configuration changes. The system uses new configurations for new tunnel negotiations. The system continues to use previous configurations that created the tunnels for ongoing operations (such as rekeying) of the existing tunnel.
QoS interactions
The ISA can interact with the queuing functions on the IOM through the ingress and egress QoS provisioning in the IES or IP VPN service where the IPsec session is bound. Multiple IPsec sessions can be assigned to a single IES or VPRN service. In this case, QoS defined at the IES or VPRN service level is applied to the aggregate traffic coming out of, or going into, the set of sessions assigned to that service.
To keep marking relevant in the overall networking design, the following traffic-class processing is supported:
In the encapsulating direction (private to public), the system copies the traffic class of the payload IP packet header to the outer tunnel IP packet header.
In the decapsulating direction (public to private), the system can optionally copy the traffic class from the outer tunnel IP packet header to the payload IP packet header using the copy-traffic-class-upon-decapsulation command for the template, service, or router IPsec tunnel configuration.
For the tunnel-group ESA VM, if a SAP egress QoS policy is needed on a public or private tunnel SAP, the CIR of all queues configured in the policy should be zero (non-zero CIR is not supported).
OAM interactions
The ISA is IP-addressed by an operator-controlled IP on the public side. That IP address can be used in ping and traceroute commands and the ISA can either respond or forward the packets to the CPM.
For static LAN-to-LAN tunnels, in multi-active mode, ping requests to public tunnel addresses are not answered if the source address is different from the remote address of the static tunnel.
The private side IP address is visible. The status of the interfaces and the tunnels can be viewed using show commands.
Traffic that ingresses or egresses an IES or VPRN service associated with specific IPsec tunnels can be mirrored like other traffic.
Mirroring is allowed per interface (public) or IPsec interface (private) side. A filter mirror is allowed for more specific mirroring.
Redundancy
In single-active mode, every tunnel group can be configured with primary and backup ISAs. An ISA can be used as a backup for multiple IPsec groups. The ISAs are cold standby such that upon failure of the primary the standby resumes operation after the tunnels re-negotiate state. While the backup ISA can be shared by multiple tunnel groups only one tunnel group can fail to a single ISA at one time (no double failure support).
In multi-active mode, the active-mda number determines the number of ISA MDAs that are active for this tunnel group, and tunnels are spread across all active ISA MDAs. Additional ISA MDAs in this tunnel group are in cold standby.
IPsec also supports dead peer detection (DPD).
BFD can be configured on the private tunnel interfaces associated with GRE tunnels and used by the OSPF, BGP or static routing that is configured inside the tunnel.
SR OS also supports multichassis IPsec redundancy, which provides 1:1 stateful protection against ISA failure or chassis failure.
Statistics collection
Input and output octets and packets per service queue are used for billing end customers who are on a metered service plan. Because multiple tunnels can be configured per interface, the statistics can include multiple tunnels. These can be viewed in the CLI and SNMP.
Reporting (syslog, traps) for authentication failures and other IPsec errors are supported, including errors during IKE processing for session setup and errors during encryption or decryption.
A session log indicates the sort of SA setup when there is a possible negotiation. This includes the setup time, teardown time, and negotiated parameters (such as encryption algorithm) as well as identifying the service a particular session is mapped to, and the user associated with the session.
Security
The ISA module provides security utilities for IPsec-related service entities that are assigned to interfaces and SAPs. These entities (such as card, MS-ISA2 module, and IES or VPRN services) must be enabled in order for the security services to process. The module only listens to requests for security services from configured remote endpoints. In the case of a VPN concentrator application, these remote endpoints could come from anywhere on the Internet. In the cases where a point-to-point tunnel is configured, the module listens only to messages from that endpoint.
GRE tunnel multicast support
GRE tunnels support unicast and multicast IP packets as payload. From a multicast prospective, a GRE tunnel IP interface (associated with a private tunnel SAP) can be configured as an IGMP interface or as a PIM interface; MLD is not supported. The following multicast features are supported:
IGMP versions 1, 2 and 3
IGMP import policies
IGMP host tracking
static IGMP membership
configurable IGMP timers
IGMP SSM translation
multicast CAC
per-interface, per-protocol (IGMP/PIM) multicast group limits
MVPN support (draft-rosen)
MVPN support (BGP-MPLS)
PIM-SM and SSM operation
PIM BFD support
configurable PIM timers
configurable PIM priority
PIM tracking support
PIM ECMP (bandwidth or hash-based)
static multicast route
IPv6 over IPv4 GRE tunnel
IPv6 payload packets can be delivered over an IPv4 GRE tunnel. In this scenario the two endpoints of the GRE tunnel have IPv4 addresses and the VPRN or IES SAP interface to the tunnel is an IPv6 only or dual-stack IPv4/IPv6 interface. IPv6 over IPv4 GRE tunneling allows IPv6 islands to be connected over an IPv4 only transport infrastructure.
To configure a tunnel to carry IPv6 payload, the tunnel must be configured with at least one dest-ip that contains an IPv6 address (global unicast and/or link local). A tunnel can have up to 16 dest-ip addresses (IPv4 and IPv6 together). For a tunnel to come operationally up all the dest-ip addresses must be part of locally configured subnets (associated with the private tunnel interface).
To forward IPv6 traffic through a tunnel supporting IPv6 payload, a dynamic routing protocol (such as BGP or OSPFv3) can be configured to run inside the tunnel (by associating the protocol with the private tunnel interface) or else an IPv6 static route next-hop equal to a dest-ip of the tunnel can be used.
IPv6 payload packets larger than 1280 bytes (the minimum IPv6 MTU) and also larger than the configured ip-mtu value of the tunnel are always discarded. If the commands in the following context are configured under the tunnel, ICMPv6 Packet-Too-Big messages are generated and sent back to the originating host when discards occur because of the private side IP MTU being exceeded:
- MD-CLI
configure ipsec tunnel-template icmp6-generation pkt-too-big
- classic
CLI
configure ipsec tunnel-template icmp6-generation packet-too-big
IKEv2
IKEv2, defined in RFC 4306, Internet Key Exchange (IKEv2) Protocol, is the second version of the Internet Key Exchange Protocol. The main driver of IKEv2 is to simplify and optimize IKEv1. An IKE_SA and a CHILD_SA can be created with only four IKEv2 message exchanges. IKEv2 is supported with the following features:
static LAN-to-LAN tunnel
dynamic LAN-to-LAN tunnel
remote-access tunnel
pre-shared-key authentication, certificate authentication, EAP (remote-access tunnel only)
liveness check
IKE_SA rekey
CHILD_SA rekey (full Traffic-Selector support including protocol and port range)
extended ESP sequence number
IKEv2 traffic selector and TS-list
The SR OS IKEv2 implementation supports the following traffic selectors:
-
IPv4/IPv6 address range
-
IP protocol ID
-
protocol port range
Port range (including OPAQUE ports) is supported for the following protocols:
-
TCP
-
UDP
-
SCTP
-
ICMP
-
ICMPv6
-
MIPv6
With ICMP and ICMPv6, the system treats the most significant 8 bits of the IKEv2 TS port value as the ICMP message type and the least significant 8 bits as ICMP code.
With MIPv6, the system treats the most significant 8 bits of the IKEv2 TS port value as the mobility header type.
With ICMP, ICMPv6, and MIPv6, the port value in TSi is the value that the tunnel initiator can send, and the port value in TSr is the value that the tunnel responder can send.
The SR OS supports OPAQUE as a TS port selector. An OPAQUE port means that the corresponding CHILD_SA only accepts packets that are supposed to have port information but do not, such as when a packet is a non-initial fragment.
The system allows users to configure a TS-list for each IPsec gateway, applied to both IKEv2 remote access tunnels and dynamic LAN-to-LAN tunnels. Each TS-list contains a local part and a remote part, with each part containing up to 32 entries. Each entry can contain address ranges or subnets, protocols, and port range configurations.
The local part of the TS-list represents the traffic selector for the local system, while the remote part is for the remote peer. If a TS-list is applied on an IPsec gateway, and the system is the tunnel responder, then the local part is TSr and the remote part is TSi.
Combinations of address range, protocol, and port range are not allowed to overlap between entries in the same TS-list.
The system performs traffic selector narrowing as follows.
-
For each TS in the received TSi/TSr, independent address, protocol, and port narrowing is performed. The resulting TS-set is the combination of the address, protocol, and range intersections.
-
The collected TS-set is used as the TSi/TSr.
For a remote access tunnel, TSi narrowing results in an intersection between the following three TSis:
-
the TSi received from the client
-
the remote part configuration of the TS-list
-
a generated TS based on the assigned internal address
-
address (the assigned internal address)
-
protocol (any)
-
port range (any)
-
The following is an example of a dynamic LAN-to-LAN tunnel.
The configured TS-list local part is as follows:
-
Entry 1: 10.10.1.0 → 10.10.1.20, udp, port 100 → 200
-
Entry 2: 10.20.1.0 → 10.20.1.20, udp, port 300 → 400
The peer proposes the following TSr:
-
Entry 1: 10.10.1.1 → 10.10.1.5, udp, port 110 → 150
-
Entry 2: 10.10.1.6 → 10.10.1.10, udp, port 180 → 210
-
Entry 3: 10.10.1.15 → 10.10.1.28, udp, port 120 → 160
-
Entry 4: 10.20.1.15 → 10.20.1.28, tcp, port 250 → 450
The intersections for the proposed entries are as follows:
-
Entry 1: 10.10.1.1 → 10.10.1.5, udp, port 110 → 150
-
Entry 2: 10.10.1.6 → 10.10.1.10, udp, port 180 → 200
-
Entry 3: 10.10.1.15 → 10.10.1.20, udp, port 120 → 160
-
Entry 4: 10.20.1.15 → 10.20.1.20, tcp, port 300 → 400
The resulting TSr system return would be:
-
10.10.1.1 → 10.10.1.5, udp, port 110 → 150
-
10.10.1.6 → 10.10.1.10, udp, port 180 → 200
-
10.10.1.15 → 10.10.1.20, udp, port 120 → 160
-
20.20.1.15 → 20.20.1.20, tcp, port 300 → 400
If more than 32 entries are returned, the system rejects the ts-negotiation and returns TS_UNACCEPTABLE to the peer.
For dynamic LAN-to-LAN tunnels, the system can automatically create a reverse route in a private VRF to route clear traffic into the tunnel. The reverse route is created based on the address range part of the narrowed TSi of the CHILD_SA. If there are multiple TSs in the TSi that have overlapping address ranges, the system creates one or more minimal subnet routes that can cover all address ranges in the TSi. If the auto-created reverse route overlaps with an existing reverse route that points to the same tunnel, the system chooses the route with the larger subnet. If the existing route points to a different tunnel, then CHILD_SA creation fails.
For RADIUS authentication options, such as psk-radius, cert-radius, or eap, the RADIUS server can optionally return a TS-list name via the VSA Alc-IPsec-Ts-Override in the access-accept message, which overrides the TS-list name configured via the CLI.
In the event of a CHILD_SA rekey, if the system is a rekey initiator, it sends the current in-use TS to the peer and expect the peer to return the same TS. If the system is a rekey responder, the system does the same narrowing as was done during CHILD_SA creation.
Configuration of a TS-list can be changed without shutting down the IPsec gateway, although the new TS-list only applies to the subsequent rekey or to the new CHILD_SA creation, and does not affect established CHILD_SAs.
IKEv2 fragmentation
In some cases, an IKEv2 message can large, like an IKE_AUTH message with certificate payload. This is likely to cause the IKEv2 packet to be fragmented into a few smaller IP packets. However, in some deployments, there could be devices or network policing, rate limiting or even dropping UDP fragments. In these cases, the SR OS supports fragmenting IKEv2 messages on the protocol level, as specified in RFC 7383, Internet Key Exchange Protocol Version 2 (IKEv2) Message Fragmentation.
This feature is enabled by configuring the an MTU using the following command:
- MD-CLI
configure ipsec ike-policy ike-version-2 ikev2-fragment mtu
- classic
CLI
configure ipsec ike-policy ikev2-fragment
The specified MTU is the maximum size of IKEv2 packet.
The system only enables IKEv2 fragmentation for a specific tunnel when the ikev2-fragment is configured and the peer also announces its support via sending a IKEV2_FRAGMENTATION_SUPPORTED notification.
SHA2 support
According to RFC 4868, Using HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 with IPsec, the following SHA2 variants are supported for authentication or pseudo-random functions:
Use HMAC-SHA-256+ algorithms for data origin authentication and integrity verification in IKEv1/2, ESP:
AUTH_HMAC_SHA2_256_128
AUTH_HMAC_SHA2_384_192
AUTH_HMAC_SHA2_512_256
For use of HMAC-SHA-256+ as a PRF in IKEv1/2:
PRF_HMAC_SHA2_256
PRF_HMAC_SHA2_384
PRF_HMAC_SHA2_512
IPsec client lockout
An optional lockout mechanism can be enabled to block malicious clients and prevent them from using invalid credentials to consume system resources, as well as to prevent malicious users from guessing credentials such as a pre-shared key. This mechanism can be enabled by using the lockout command.
If the number of failed authentication attempts from a particular IPsec client exceeds a configured threshold during a specified time interval, the client is blocked for a configurable period of time. If a client is blocked, the system drops all IKE packets from the source IP address and port.
The following authentication failures are counted as failed authentication attempts:
IKEv1
psk: failed to verify the HASH_I payload in main mode
plain-psk-xauth:
failed to verify the HASH_I payload in main mode
RADIUS access-reject received
IKEv2
psk: failed to verify the AUTH payload in the auth-request packet
psk-radius:
failed to verify the AUTH payload in the auth-request packet
RADIUS access-reject received
cert:
failed to verify the AUTH payload in the auth-request packet
failed to verify the peer’s certification to configured trust-anchors
cert-radius:
failed to verify the AUTH payload in the auth-request packet
failed to verify the peer’s certification to configured trust-anchors
RADIUS access-reject received
eap: RADIUS access-reject received
Other failures, such as being unable to assign an address, are not counted.
The AUTH failure counter is reset by either a successful authentication before the client is blocked, the expiration of a block timer, or the expiration of the duration timer.
If multiple IPsec clients behind a NAT device share the same public IP address, a limit for the maximum number of clients or ports behind the same IP address can be configured. If the number of ports exceeds the configured limitation, all ports from that IP address are blocked.
The clear ipsec lockout command can also be used to manually clear a lockout state for the specified clients.
IPsec tunnel CHILD_SA rekey
SR OS supports CHILD_SA rekeying for both IKEv1 and IKEv2. The following are the behaviors for the rekey:
IKEv1 or IKEv2 CHILD_SA rekey initiator
outbound
The system immediately switches to the new security association (SA) after a new SA is created.
-
inbound
The old SA is kept for three minutes after the new SA is created. Then, it is removed, and upon removal:
-
IKEv1
The system does not send a delete message upon removal.
-
IKEv2
The systems send a delete message upon removal.
-
IKEv1or IKEv2 CHILD_SA rekey responder
outbound
The system keeps using the old SA for 25 seconds after the new SA is created before switching to the new SA. If a delete message of the old SA is received before 25 seconds, the system removes the old SA and starts using new SA.
-
inbound
The old SA is kept for rest of its lifetime. However, if a delete message is received to close the corresponding outbound SA, then the system removes the corresponding inbound SA before its lifetime expires. The system sends a delete message when the old SA lifetime expires.
If the old SA lifetime expires before the 25 seconds or three minutes mentioned above, the old SA is removed upon expiration and the system sends a delete message.
Multiple IKE/ESP transform support
For IPsec tunnels or IPsec gateways, the SR OS allows users to configure up to four IKE transform and four IPsec transform configurations for IKE and ESP traffic.
- MD-CLI
configure service vprn interface sap ipsec-tunnel key-exchange dynamic
- classic
CLI
configure service vprn interface sap ipsec-tunnel dynamic-keying
IKE transform includes the following configurations:
-
IKE encryption algorithm
-
IKE authentication algorithm
-
Diffie-Hellman group
-
IKE SA lifetime
IPsec transform includes the following configurations:
-
ESP encryption algorithm
-
ESP authentication algorithm
-
Diffie-Hellman group for CHILD SA rekey with PFS
-
CHILD SA lifetime
If multiple IKE and IPsec transform parameters are configured for IPsec gateways and IPsec tunnels, the system uses the configured transforms to negotiate with the peer. This negotiation allows IPsec gateways and IPsec tunnels to support peers with different crypto algorithms.
Reverse routes for dynamic LAN-to-LAN IPsec tunnels
With dynamic LAN-to-LAN IPsec tunnels, one or multiple reverse routes can be automatically created per CHILD_SA in a private service, based on traffic selectors in the negotiated TSi. Use the following command to enable the creation of reverse routes.
configure ipsec tunnel-template sp-reverse-route
For a specific CHILD_SA, its TSi contains one or multiple address ranges. The system creates one or multiple reverse routes with the largest prefix length to cover all the ranges in the TSi. If a resulting route overlaps with an existing route of the same tunnel, only the route with the smaller prefix length is kept. If a resulting reverse route is a default route, it is ignored if the ignore-default-route command option is enabled in the tunnel template.
Use the following command to configure the acceptance of overlapping DL2L reverse routes.
configure service vprn ipsec overlapping-reverse-route
If a reverse route of an in-setup CHILD_SA overlaps with an existing reverse route from a different tunnel, the system handles it according to following command configurations:
- If the overlapping-reverse-route command is configured as false
(disabled):
- If the allow-reverse-route-override-type command (allow-reverse-route-override in classic CLI) is not configured, the in-setup SA fails, resulting in the removal of its tunnel.
- If allow-reverse-route-override-type is configured to same-idi and the in-setup SA belongs to a tunnel that has the same IKEv2 IDi as the corresponding tunnel of the existing reverse route, the system removes the existing tunnel (which includes the existing SA and all others belonging to that tunnel) and creates the in-setup SA; otherwise, the in-setup SA fails.
- If allow-reverse-route-override-type is configured to any-idi, the system removes the existing tunnel (with the existing SA and all other SAs belonging to it) and creates the in-setup SA.
- If the overlapping-reverse-route command is configured as true
(enabled), the system creates the in-setup SA and also keeps the existing SA. The system
installs all overlapping-but-not-same routes in the route table with their associated metric
and preference values configured for the reverse-route command in the
tunnel template. If there are same routes from different tunnels, the system selects the
route to install based on the following rules:
- The lower preference route is preferred.
- The lower metric route is preferred.
- The non-shunting next hop is preferred.
- The routes to install are selected from the set of routes where conditions a, b, and c are equal. The quantity of routes to install is the quantity of ECMP next hops specified by the ECMP configuration of the private service (implicitly 1 when ECMP is disabled in the private service). The routes are selected from the set in order of the lowest values returned by the strcmp() function comparing their next-hop strings.
Using certificates for IPsec tunnel authentication
SR OS supports X.509v3 certificate authentication for IKEv2 tunnel (LAN-to-LAN tunnel and remote-access tunnel). SR OS also supports asymmetric authentication. This means the SR OS and the IKEv2 peer can use different methods to authenticate. For example, one side could use pre-shared key and the other side could use a certificate.
SR OS supports certificate chain verification. For a static LAN-to-LAN tunnel or IPsec gateway, there is a configurable trust-anchor-profile which specifies the expecting CAs that should be present in the certificate chain before reaching the root CA (self-signed CA) configured in the system.
The SR OS’s own key and certificate are also configurable per tunnel or IPsec gateway.
When using certificate authentication, the SR OS uses the subject of the configured certificate as its ID by default.
IKEv2 digital signature authentication
RFC 7427 Signature Authentication in the Internet Key Exchange Version 2 (IKEv2) defines a new IKEv2 AUTH payload method which not only indicates the type of public key, but also the hash algorithm that used to generate the signature; it also includes a new IKEv2 notification: SIGNATURE_HASH_ALGORITHMS, which is used to signal support of RFC 7427 and a list of support hash algorithms to a peer.
RFC 7427 is the default way to perform certificate authentication for IKEv2. The system negotiates its support with the peer as follows:
-
sending
-
as tunnel initiator, includes SIGNATURE_HASH_ALGORITHMS in the IKE_SA_INIT request.
-
as tunnel responder, includes SIGNATURE_HASH_ALGORITHMS in IKE_SA_INIT response only if the received IKE_SA_INIT request includes it.
-
includes the SHA1/SHA2-256/SHA2-384/SHA2-512 hash algorithms in SIGNATURE_HASH_ALGORITHMS
-
-
receiving
-
If the peer does not include SIGNATURE_HASH_ALGORITHMS in the IKE_SA_INIT packet, then it does not support RFC 7427 and the system uses an RSA Digital Signature for the RSA key(value 1), and DSS Digital Signature (value 3) for the DSA key to generate the AUTH payload.
Note: If the ECDSA key is selected in the cert-profile entry, then the tunnel setup fails in the system. -
If the peer sends SIGNATURE_HASH_ALGORITHMS, then the system uses RFC 7427 and the strongest hash algorithms that is supported by both sides to generate the AUTH payload. If there is no common hash algorithms supported by both sides, the system falls back to RSA Digital Signature (Auth Method value 1) or DSS Digital Signature (Auth Method value 3).
Note: If the selected key is an RSA key, there are specific cases that have a short RSA key with long hash algorithm. The system falls back to RSA Digital Signature for RSA key (value 1) even when both sides send SIGNATURE_HASH_ALGORITHMS and there are common hash algorithms.To verify the received digital signature of the AUTH payload, the peer must uses one of the algorithms in the SIGNATURE_HASH_ALGORITHMS that the system sends. Otherwise, the tunnel setup fails.
-
The system continues to use CAs in received cert-request payloads to select the cert-profile entry; if the selected entry is an RSA key, the system needs to decide to whether use PKCS#1-1.5 or RSASS-PSS to generate the signature by using the value set by the following command.
configure ipsec cert-profile entry rsa-signature
Trust-anchor profile
SR OS supports multiple trust-anchors per IPsec tunnel or gateway. Users can configure a trust-anchor-profile that includes up to eight CAs. The system builds a certificate chain by using the certificate in the first certificate payload in the received IKEv2 message. If any of configured trust-anchor CAs in the trust-anchor-profile appears in the chain, then authentication is successful. Otherwise, authentication is failed.
SR OS only supports processing of up to 16 hashes for the trust-anchor list from other products. If the remote end is sending more than 16, and a certificate match is in the > 16 range, the tunnel remains down with authentication failure.
Cert-profile
SR OS supports sending different certificate/chain according to the received IKEv2 certificate-request payload. This is achieved by configuring a cert-profile, which allows up to eight entries. Each entry includes a certificate and a key and, optionally, also a chain of CA certificates.
The system loads the cert and key configured in a cert-profile into memory and builds a chain. Compare-chain is performed for the certificate configured in each entry of the cert-profile upon enabling of the cert-profile. These chains are used in IKEv2 certificate authentication. If a chain computation cannot be completed for a configured certificate, then the corresponding compare-chain is empty or only partially computed.
Because there can be multiple entries configured in the cert-profile, the system needs to pick the cert and key in the correct entry that the other side expects to receive. This is achieved by a lookup of the CAs within one cert-request payload or multiple cert-request payloads in the compare-chain and then picking the first entry that has a cert-request CA appearing in its chain. If there is no such cert, the system picks the first entry in the cert-profile. The first entry shown in the output below, is the first configured entry in the cert-profile. The entry-id of first entry does not have to be 1.
For example, there are three CA listed in certificate-request payload: CA-1, CA-2 and CA-3, and there are two entries configured in the cert-profile as follows:
MD-CLI
cert-profile "cert-profile-1" {
entry 1 {
cert "cert-1"
key "key-1"
}
entry 2 {
cert "cert-2"
key "key-2"
send-chain {
ca-profile ["CA-1" "CA-2"]
}
}
}
classic CLI
cert-profile ‟cert-profile-1”
entry 1
cert ‟cert-1”
key ‟key-1”
entry 2
cert ‟cert-2”
key ‟key-2”
send-chain
ca-profile ‟CA-1”
ca-profile ‟CA-2”
The system builds two compare-chains: chain-1 for cert-1 and chain-2 for cert-2. Assume CA-2 appears in chain-2, but CA-1 and CA-3 do not appear in either chain-1 or chain-2. Then the system picks entry 2.
After a cert-profile entry is selected, the system generates the AUTH payload by using the configured key in the selected entry. The system also sends the cert in the selected entry as ‟certificate” payload to the peer.
If a chain is configured in the selected entry, then one certificate payload is needed for each certificate in the configured chain. The first certificate payload in the IKEv2 message is the signing certificate, which is configured by the cert command in the chosen cert-profile entry. With the above example, the system sends three certificate payloads: cert-2, CA-1,CA-2.
The following CA chain-related enhancements are supported:
-
Enabling a ca-profile triggers a recomputation of the compute-chain in related cert-profiles. The system also generates a new log-1 to indicate a new compute-chain has been generated; the log includes the ca-profile names on the new chain. Another log (log-2), is generated if the send-chain in a cert-profile entry is not in the compute-chain because of this ca-profile change. Another log is generated if the hash calculation for a certificate under a ca-profile has changed.
-
When enabling a cert-profile, the system allows the CAs in the send-chain, not in the compute-chain. The system also generates log-2 as above.
-
The system allows changes of the configuration of send-chain without disabling the cert-profile.
-
When a configure root CA is cross-signed by another CA, multiple overlapping compare-chains for a specific certificate profile entry may occur. Choose one compare-chain by executing the following command to specify the tiebreak CA.
configure ipsec cert-profile entry compare-chain-include
Video wholesale example
As satellite head-end locations can be costly, many municipal and second tier operators cannot justify the investment in their own ground station to offer triple play features. However, it is possible for a larger provider or a cooperative of smaller providers to unite and provide a video head-end. Each retail subscriber can purchase content from this single station, and receive it over IP. However, encryption is required so the signal cannot be understood if intercepted. A high speed encrypted tunnel is preferred over running two layers of double video protection which is cumbersome and computationally intensive.
Video wholesale configuration shows an example of video wholesale configuration.
1:1 Multichassis IPsec redundancy
See "Multi-Chassis IPSec Redundancy" and "N:M MC-IPsec Redundancy" in the 7450 ESS and 7750 SR Multiservice ISA and ESA Advanced Configuration Guide for MD CLI for information about advanced configurations.
This section applies to the 7750 SR, the 7450 ESS, and VSR.
Multichassis IPsec redundancy (MC-IPsec) provides a 1:1 (active/standby) IPsec stateful failover mechanism between two chassis.
The following describes features about MC-IPsec:
-
This feature provides protection against ISA failure and chassis failure.
-
MC-IPsec is supported for all types of IKEv2 tunnels, including static LAN-to-LAN, dynamic LAN-to-LAN and remote-access tunnels.
-
This feature is supported only on multi-active tunnel groups.
-
The granularity of failover is per tunnel group, which means a specific tunnel group could failover to the standby chassis independent of other tunnel groups on the master chassis.
-
The components included in this feature as shown in the following table.
Table 2. MC-IPsec redundancy feature components MC-IPsec redundancy feature component Description Master election
MC-IPsec Mastership Protocol (MIMP) runs between chassis to elect master, MIMP runs for each tunnel group independently.
Synchronization
Multichassis Synchronization (MCS) synchronizes IPsec states between chassis.
Routing
Routing features include the following:
-
MC-IPsec aware routing attracting traffic to the master chassis
-
shunting support
-
MC-IPsec aware VRRP
-
Architecture
The overall MC-IPsec redundancy architecture is displayed in MC-IPsec architecture.
MIMP
With MIMP enabled, there is a master chassis and a backup chassis. The state of the master or standby is per tunnel group. For example (Master and backup chassis example), chassis A and B, for tunnel-group 1, A is master, B is standby; for tunnel group 2, A is standby, B is master.
Master | Standby | |
---|---|---|
Tunnel group 1 |
A |
B |
Tunnel group 2 |
B |
A |
All IKEv2 negotiation and ESP traffic encryption and decryption occurs on the master chassis. If the backup chassis receives this traffic, if possible, it shunts it to the master.
There is a mastership election protocol (MIMP) running between the chassis to elect the master. This is an IP-based protocol to avoid any physical topology restrictions.
A central BFD session could be bound to MIMP to achieve fast chassis failure detection.
MIMP protocol states
There are five MIMP states:
-
discovery
-
notEligible
-
eligible
-
standby
-
master
The five MIMP states are described as follows:
- discovery
Upon enabling MC-IPsec for the tunnel group, for example:
-
system starts up
-
enable the MC-IPsec peer
-
enable the MC-IPsec tunnel-group
Functionally, this means traffic to the ISA is blackholed with no shunting.
If the peer is reached before the configured discovery interval has expired, the state is changed to whatever the MIMP decides.
If the peer is not reached before the discovery interval has expired, the state is changed to eligible or notEligible depending on the operational status of the tunnel group.
-
-
notEligible
The tunnel group is operationally down. Functionally, this means blackhole traffic to the ISA and no shunting.
-
eligible
The peer is not reachable or the associated BFD session is down but the tunnel group is operationally up. Functionally, this means the ISA processes traffic.
-
standby
Peer is reachable, elected standby. Functionally, this means blackhole traffic to ISA and shunting if possible.
-
master
Peer is reachable, elected master. Functionally, this means the ISA processes traffic.
Election logic
The following election logic is executed when MIMP packets are exchanged.
-
Calculate master eligibility.
-
Set masterEligible to TRUE if the local tunnel group is operationally up, otherwise FALSE.
-
Set peerMasterEligible to TRUE if the peer’s tunnel group is operationally up, otherwise FALSE.
-
-
Elect based on eligibility.
-
If masterEligible and not peerMasterEligible, elect self master → DONE.
-
If not masterEligible and peerMasterEligible, elect peer master → DONE.
-
If not masterEligible and not peerMasterEligible, no master → DONE.
-
-
Apply stickiness rules (mastership tends not to change).
-
If l was ‟acting master” and peer was not ‟acting master”, then elect self master -> DONE.
-
If 1 was not ‟acting master” and peer was ‟acting master”, then elect peer master -> DONE.
An ‟acting master” is either in MIMP state ‟master” or ‟eligible”.
-
-
Elect based on priority and number of active ISAs.
-
If my priority is higher than peer, elect self master → DONE.
-
If peer priority is higher than mine, elect peer master → DONE.
-
If I have more active ISA than peer, elect self master → DONE.
-
If peer has more active ISA than me, elect peer master → DONE.
-
The tie breaker:
-
If the local chassis’ MIMP source address is higher than the peer’s, elect self master → DONE.
-
Elect peer master → DONE.
Protection status
Each MC-IPsec-enabled tunnel group has a protection status, which could be one of following:
-
notReady
The tunnel group is not ready for a switchover because there is either no elected standby to takeover, or there are pending IPsec states which need to be synced. If switchover occurs with this status, there could be a significant traffic impact.
-
nominal
The tunnel group is in a better situation to switchover than notReady. However, traffic still may be impacted.
Protection status serves as an indication for the operator to decide the optimal time to perform a controlled switchover.
show redundancy multi-chassis mc-ipsec peer tunnel-group
Other details
Mastership election is per tunnel group.
MIMP is running in the base routing instance.
-
MIMP uses the configured value of the following command as the source address.
configure redundancy multi-chassis peer source-address
If not configured, the system address is used.
The priority range is from 0 to 255.
When an MC-IPsec tunnel group enters standby from acting master, the tunnel group is restarted.
When a tunnel group is disabled under the MC-IPsec configuration (add a tunnel group to an MC-IPsec configuration, or when an MC-IPsec-enabled tunnel group is disabled):
All tunnels in the tunnel group are deleted and reinstalled to the ISA.
All IKE states associated with those tunnels are locally purged from the MS-ISAs.
No IKE messages are sent to the IKE peer.
These behaviors occur regardless of the presence of a redundant chassis or the state of a redundant chassis.
With MC-IPsec enabled:
auto-establish is blocked.
-
For DPD configuration, the reply-only command option must be enabled.
configure ipsec ike-policy dpd reply-only
Routing
Routing in public service
A /32 route of the local tunnel address is created automatically for all tunnels on the MC-IPsec enabled tunnel group.
This /32 route can be exported to a routing protocol by a route policy. The protocol type of the route policy is IPsec.
To attract traffic to the master chassis, a route metric of these /32 routes could be set according to the MIMP state, a metric from the master chassis is better than a metric from the standby chassis. There are three available states that can be used in the following commands in the route policy entry configuration.
- MD-CLI
configure policy-options policy-statement entry from state configure policy-options policy-statement named-entry from state
- classic
CLI
configure router policy-options policy-statement entry from state
-
IPsec-master-with-peer
Corresponding MIMP states: master
-
IPsec-master-without-peer
Corresponding MIMP states: eligible
-
IPsec-non-master
Corresponding MIMP states: discovery/standby
However, if the standby chassis receives IPsec traffic, the traffic is shunted to the master chassis by forwarding to a redundant next-hop. The redundant next-hop is an IP next-hop in the public routing instance.
Routing in private services
For static LAN-to-LAN tunnels, the static route with the IPsec tunnel as the next-hop could be exported to a routing protocol by a route policy. The protocol type remains static. For dynamic LAN-to-LAN tunnels, the reverse-route could be exported to a routing protocol by a route policy. The protocol type is ipsec. For remote-access tunnel, the private interface route could be exported to a routing protocol by a route policy.
Similar to routing in public services, the route metric of the above the routes could be set according to the MIMP state. Only a static route with an IPsec tunnel as the nexthop and reverse route has an MIMP state.
If the standby chassis receives IPsec traffic, the traffic is shunted to the master chassis by forwarding to a redundant next-hop. The redundant next-hop is an IP next-hop in a private routing instance.
Other details about shunting
Shunting only works when tunnel group is operationally up.
Shunting is not supported over auto-bind tunnels.
MC-IPsec aware VRRP
In many cases, the public side is a Layer 2 network and VRRP is used to provide link or node protection. However, VRRP and MC-IPsec are two independent processes, each has its own mastership state, which means the VRRP master could be different from MC-IPsec master. This results in shunting traffic unnecessarily.
To address this issue, MC-IPsec aware VRRP provides a priority event in the vrrp policy: mc-ipsec-non-forwarding. If the configured tunnel group enters non-forwarding (non-master) state, the priority of the associated VRRP instance is set to the configured value. Delta priority is not supported for this type of event.
Synchronization
To achieve stateful failover, IPsec states are synced between chassis by using the MCS protocol.
Only successfully created SA after a completed INITIAL EXCHANGES or CREATE_CHILD_SA EXCHANGES is synced.
Upon switchover, the new standby chassis reboots the tunnel group.
The ESP sequence number is not synced except for the high 32 bits of extended sequence numbers.
The CLI configuration is not synced.
The time must be the same on both chassis (using NTP/SNTP to sync to the same server is an option).
Automatic CHILD_SA rekey
Because the ESP sequence number is not synced, a CHILD_SA rekey for each tunnel is initiated by the new active chassis to reset the sequence number upon switchover.
Encryption of Synced States
Transport encryption of synced IPsec states can be configured using the following command, with the ipsec command option as the keychain name. This causes the system to encrypt the IPsec states during transportation between the active and standby.
configure redundancy multi-chassis peer sync transport-encryption application application-id
The key used to encrypt states is specified by the referenced keychain, which is defined in the following context:
- MD-CLI
configure system security keychains keychain
- classic
CLI
configure system security keychain
The commands in this context provide the user the ability to gracefully enable or disable encryption or change the key.
Gracefully enable encryption steps
To use a keychain for MCS IPsec, the keychain aes-128-gcm-16 entry algorithm must be configured.
Use the following steps to gracefully enable encryption. Chassis A and chassis B must both run releases that support the transport-encryption feature. Chassis A is active and chassis B is standby.
-
On chassis B, change the configuration to add MCS encryption, using a keychain
with two bidirectional entries in the following context.
- MD-CLI
configure system security keychains keychain bidirectional entry
- classic
CLI
configure system security keychain direction bi
-
For entry 1, use the following values:
-
For the entry ID, use null-key.
-
For begin-time, use now.
-
For tolerance, use forever.
-
-
For entry 2, use the following values:
-
For the algorithm, use aes-128-gcm-16.
-
For begin-time, add enough time to complete the next step (for example, if the current time is 2023/4/18 10:00 UTC, then add one hour to complete step 2, begin-time 2023/4/18 11:00 UTC).
-
Because both chassis A and chassis B are still using clear transport, A can successfully synchronize states to B.
- MD-CLI
-
On chassis A, change the configuration to add MCS encryption, using a keychain
with two bidirectional entries in the following context:
- MD-CLI
configure system security keychains keychain bidirectional entry
- classic
CLI
configure system security keychain direction bi
-
For entry 1, use the following values:
-
For the entry ID, use null-key.
-
For begin-time, use now.
-
For tolerance, use forever.
-
-
For entry-2, use the following values:
-
For algorithm, use aes-128-gcm-16.
-
For begin-time, use the same value as in step 1 , begin-time, for example, 2023/4/18 11:00:00 UTC.
-
Because both A and B can receive either clear or encrypted states, synchronization is successful.
- MD-CLI
-
After t1 (set using the begin-time command option), remove
entry 1 from both chassis using the following command.
- MD-CLI
configure system security keychains keychain bidirectional entry admin-state disable
- classic
CLI
configure system security keychain direction bi no entry
- MD-CLI
For an example configuration, see Configuring MCS encryption.
Gracefully change the key steps
Use the following steps to gracefully change the key. Chassis A and chassis B both have configured transport encryption where chassis A is active and chassis B is standby.
-
On Chassis B, change the configuration to add a new keychain, entry
y, with a new key:
-
entry x (the old entry)
For tolerance, use forever (this step can be performed without administratively disabling the entry).
-
entry y:
-
For algorithm, use aes-128-gcm-16.
-
For begin-time, add enough time to ensure the there is enough time to complete the next step (for example, if the current time is 2023/4/18 10:00 UTC, then add one hour to complete step 2, begin-time 2023/4/18 11:00 UTC).
-
At this point, both A and B are still configured to use the old key (entry x) for transport, so A successfully synchronizes states to B.
-
-
On chassis A, change the configuration to add a new keychain, entry
y, with new key:
-
entry x (the old entry)
For tolerance, use forever (this can be performed without shutting down the entry).
-
entry y:
-
For algorithm, use aes-128-gcm-16.
-
For begin-time, use the same value as in step 1. begin-time 2023/4/18 11:00 UTC.
-
-
-
After t1 (set using the begin-time command option), both A
and B begin to use entry y. Remove entry x
from both chassis using the following command.
- MD-CLI
configure system security keychains keychain bidirectional entry admin-state disable
- classic
CLI
configure system security keychain direction bi no entry
- MD-CLI
MC-IPsec responder only
An MC-IPsec pair must only act as an IKEv2 responder (except for the automatic CHILD_SA rekey on switchover). To enable this behavior, configure the following command.
configure isa tunnel-group ipsec-responder-only
N:M MC-IPsec redundancy
In addition to 1:1 MC-IPsec, the system also supports N:M multichassis IPsec stateful redundancy. The term N:M is used to refer to this feature. N:M provides additional redundancy and potential cost saving compared to 1:1 MC-IPsec.
N:M allows overall N active nodes and tunnel groups to be backed up by the M standby node and tunnel group. The number represented by N can be larger than, equal to, or smaller than the number represented by M.
The following graphic shows a typical N:M configuration.
Redundancy domain
-
One node is elected to be the active node for the tunnel group
-
Other nodes are the standby node for the tunnel group
Tunnel states are synchronized between all nodes in the domain.
A node may have multiple tunnel groups, and in turn, participate in multiple redundancy domains. See Election for information about how the election of nodes is determined.
Redundancy role
Within a specific redundancy domain, each node has a designated role and an operational role:
- Designated role
Designated roles are user-configured as the designated active (DA) or designated standby (DS).
- Operational role
Operational roles are decided by election protocol during runtime as operational active (OA) or operational standby (OS).
The user can configure each node in the domain as either DA or DS. Any combination of DA:DS is allowed within a domain; however, only one node is elected as OA, other nodes are OS. A designated active role may be elected as OS and a DS may be elected as operationally active.
ISA tunnel-member pool
N:M allows the use of a single set of ISAs to backup multiple tunnel groups. This is achieved by using the tunnel-member-pool command. The tunnel-member pool includes a set of ISAs, as well as a tunnel group with a DS role that refers to the tunnel-member pool instead of directly referring to the ISA. Multiple DS tunnel groups can refer to the same tunnel-member pool, and in turn, share same set of ISAs.
When a failover occurs, if a DS tunnel group is elected to become the OA, the system then takes the required ISAs out of the underlying tunnel-member pool and uses them to populate the tunnel group and the CPM downloads corresponding tunnel states to the selected ISAs. The number of ISAs taken out of the underlying tunnel member pools equals the value configured by the following command in the DS tunnel group:
- MD-CLI
configure isa tunnel-group multi-active active-isa-number
- classic
CLI
configure isa tunnel-group active-mda-number
If there is enough ISA left in the tunnel member pool for other DS tunnel groups, additional failovers can be supported.
A DA tunnel group refers to the ISA directly, and synchronized states are downloaded to the ISA directly. In the case of a DS tunnel group, synchronized tunnel states are stored first on the CPM and only downloaded to the ISA upon failover. Because of this difference, the traffic impact during a failover is larger than when failing over to a DS tunnel group than to a DA tunnel group.
A DS tunnel group can only refer to a tunnel-member pool, not directly to the ISA.
By default, the synced tunnel states are only downloaded to ISA on switchover. When the optional HA mode for a tunnel-member pool is configured, the CPM pre-downloads the synced tunnel states of all the tunnel groups associated with a pool to every ISA in the pool. After the switchover, the system picks the required number of ISAs out of the pool and activates the states of the switched-over tunnels. Hence, the switchover to a DS is much faster than the default behavior. However, when compared with failover to DA, this mode is still slower because of the extra time required to activate the states.
With HA, a scale mode is specified, which defines the maximum number of tunnels of all tunnel groups associated with a pool.
Redundancy state and protection status
For each participating domain, an N:M node has a redundancy state with one of following values:
-
Discovery
The node's initial peer discovery, for example, when the system boots up.
-
notEligible
The node is not eligible to be elected as OA, for example, when the local ISA fails.
-
Eligible
The node is unable to reach election consensus with its peers, but the node can function locally as OA, for example, the local tunnel group is up but unable to reach its peers.
-
Standby
The node is able to reach election consensus with its peers and is elected as OA.
-
Active
The node is able to reach election consensus with its peers and is elected as OA.
The system also has a protection status for each participating domain that can be Nominal or notReady. In case of a switchover, traffic impact of notReady can be higher than Nominal.
The protection status serves as an indication for to decide the optimal time to perform a controlled switchover.
Use the following command to check the redundancy state and protection status for a domain:
show redundancy multi-chassis ipsec-domain
Election
The election protocol MIMPv2, for N:M, is used to elect the OA node in a domain. A full meshed MIMPv2 peering is required between all nodes in the domain for each participating domain. The system has a user-configurable priority. The designated role, priority, and router ID impact how an active node is elected.
-
DA is preferred over DS.
-
With the same designated role, the node with a higher priority is preferred.
-
With the same designated role and priority, the node with the higher router ID is preferred. MIMPv2 uses the router ID as the node identification. This can be different from the MIMPv2 packet’s IP address.
A central BFD session can be bound to a MIMPv2 peering to accelerate node failure detection.
A failover is triggered by one of following events:
-
node failure
-
ISA failure
-
manually forcing a switchover. Use the following command to manually force a switchover.
tools perform redundancy multi-chassis mc-ipsec force-switchover domain
Because a domain can contain up to four nodes, there can be up to three failovers to three different nodes for a tunnel group. This gives more node-level redundancy than the 1:1 MC-IPsec feature.
The following example shows the election.
Domain 1 contains node A, B, C, and D.
Node |
Designated role |
Operational role |
Priority |
---|---|---|---|
A |
DA |
OA |
200 |
B |
DA |
OS |
100 |
C |
DS |
OS |
200 |
D |
DS |
OS |
150 |
If node A fails, then the following occurs.
-
First, node A fails over to node B, because B is DA and C and D are DS. DA is preferred over DS.
-
If node B is not able to recover (if node B also failed), then it fails over to node C because both C and D are DS. Node C has the higher priority and as a result is selected as OA.
-
Lastly, if both node B and C are unable to cover, the only available node D is elected as OA.
Revertive
The revertive function allows a node in an N:M domain to automatically take over as the active router in the domain when it becomes eligible. In this example, the node is called the challenger. To be eligible, the challenger must meet all the following criteria:
-
The domain must be configured as revertive on the challenger.
-
The challenger must continuously have been in a redundancy state, which means on standby for the last 60 seconds.
-
The challenger must continuously have been in a protection status, that is, nominal for the last 60 seconds.
-
The challenger must meet the following criteria:
-
The challenger is DA while the existing OA is DS.
-
The challenger is DS while the existing OA is also DS.
-
With the same designated role, the challenger has a higher priority than the existing OA.
-
With the same designated role and priority, the challenger has a higher router ID than the existing OA.
-
If the 60-second interval for criteria 2 and 3 have elapsed, and the challenger notices that another revertive peer with better properties than in criterion 4 is present and eligible, the challenger continues for another 60 seconds before trying to take over.
DA versus DS
The following table summarizes the differences between DA and DS.
DA |
DS |
|
---|---|---|
ISA member |
N/A. Requires a dedicated ISA for each tunnel group. |
ISA member pool allows sharing the ISA across multiple tunnel groups. |
Sync |
Synchronized states are pre-downloaded to the ISA. There is less traffic impact during failover. |
Synchronized states are kept on the CPM and downloads to the ISA only upon failover. An optional HA mode allows pre-downloading states to ISA and activating upon switchover. |
Election |
DA is preferred over DS |
|
Revertive failover |
A DS challenger cannot assume the OA role from a DA node. |
|
admin ipsec display-key |
Supported in case of both OA and OS. |
Only supported as OA. |
State synchronization
To achieve stateful failover, a fully meshed MCS peering between nodes in a domain is used to synchronize IPsec states across nodes.
The following criteria is considered to synchronize IPsec states across nodes:
-
An SA is only successfully created after a completed Initial Exchanges or CREATE_CILD_SA Exchange is synced.
-
Upon switchover, the new OS node resets the tunnel group.
-
The ESP sequence number is not synchronized.
-
The CLI configuration is not synchronized.
-
The system time must be synchronized across all participating nodes (for example, using NTP or SNTP to synchronize the system time).
-
Because the ESP sequence number is not synchronized, a CHILD_SA rekey for each tunnel is initiated by the new OA to reset the sequence number on switchover.
-
MCS encryption, as described in 1:1 MC-IPsec, can also be used for N:M.
Routing
-
IPsec-master-with-peer
The corresponding redundancy states are active.
-
IPsec-master-without-peer
The corresponding redundancy states are eligible.
-
IPsec-non-master
The corresponding redundancy states are discovery, standby, or notEligible.
VRRP
configure vrrp policy priority-event mc-ipsec-non-forwarding
This is equivalent to the following command in routing:
- MD-CLI
configure policy-options policy-statement entry from state ipsec-non-master
- classic
CLI
configure router policy-options policy-statement entry from state ipsec-non-master
A VRRP policy can set the priority of the VRRP instance to a configured value after the associated tunnel group enters the redundancy state. Delta priority is not supported for this type of event.
Shunting
Optionally, if an SR OS node receives IPsec traffic, it can shunt the traffic to the OA node to minimize traffic loss.
For each routing instance, N:M allows users to define a multichassis shunting profile that specifies, for each N:M peer, the IP interface used to shunt traffic and the corresponding next hop is specified using the multi-chassis-shunt-interface command.
Specify the per-peer shunt interface using the following command.
configure router ipsec multi-chassis-shunting-profile peer multi-chassis-shunt-interface
configure service vprn ipsec multi-chassis-shunting-profile peer multi-chassis-shunt-interface
Specify the next-hop of the shunt interface using the following command.
configure router ipsec multi-chassis-shunt-interface next-hop
configure service vprn ipsec multi-chassis-shunt-interface next-hop
Because shunting is performed by forwarding traffic to the specified next hop over the shunt interface, the shunt interface must be an interface directly connected to its peer a spoke SDP-terminated interface.
Responder only
N:M states that the required node can only act as an IKEv2 responder (except for the automatic CHILD_SA rekey upon switchover). This behavior is enabled with the following command.
configure isa tunnel-group ipsec-responder-only
Coexisting tunnel groups
The system supports a 1:1 MC-IPsec tunnel group that coexists with an N:M tunnel group. A specific tunnel group cannot be both 1:1 and N:M at the same time.
Provisioning requirements
There are specific provisioning requirement for N:M to work properly, see IPsec deployment requirements for details.
Configuring N:M
-
IPsec-specific configurations, such as IKE policy, transform, IPsec tunnel, IPsec gateway, and so on
-
N:M redundancy configurations require the following:
-
Set the domain, using the following command.
configure redundancy multi-chassis peer mc-ipsec domain
-
Enable MCS using the following command.
configure redundancy multi-chassis peer sync ipsec
-
-
For the VRRP routing configuration, use the MC state in the route policy and VRRP policy.
-
Shunting configurations require the following:
-
Use either of the following commands to specify the shunt interface name and next-hop address.
configure router ipsec multi-chassis-shunt-interface configure service vprn ipsec multi-chassis-shunt-interface
-
Use either of the following commands to specify the shunt interface to use for a specific peer.
configure router ipsec multi-chassis-shunting-profile configure service vprn ipsec multi-chassis-shunting-profile
-
Use the following command to specify the shunt interface for a public or private tunnel interface.
configure service vprn interface multi-chassis-shunting-profile
-
DS tunnel-group-specific configurations require a set of ISAs to be included in the pool, using the following command.
configure isa tunnel-member-pool
DA in an N:M redundancy configuration
- MD-CLI
[ex:/configure redundancy multi-chassis] A:admin@node-2# info ipsec-domain 1 { designated-role active priority 250 tunnel-group 1 } peer 84.84.84.84 { sync { ipsec true } mc-ipsec { bfd-liveness true domain 1 { } } } peer 85.85.85.85 { sync { ipsec true } mc-ipsec { bfd-liveness true domain 1 { } } }
- classic
CLI
A:admin@node-2>config>redundancy# info ---------------------------------------------- multi-chassis ipsec-domain 1 create designated-role active priority 250 tunnel-group 1 no shutdown exit peer 84.84.84.84 create sync ipsec no shutdown exit mc-ipsec bfd-enable domain 1 create no shutdown exit exit no shutdown exit peer 85.85.85.85 create sync ipsec no shutdown exit mc-ipsec bfd-enable domain 1 create no shutdown exit exit no shutdown exit exit
DA of a route policy configuration on the private side
- MD-CLI
[ex:/configure policy-options] A:admin@node-2# info policy-statement "export400" { entry 10 { from { state ipsec-master-with-peer protocol { name [ipsec] } } action { action-type accept local-preference 255 community { add ["vprn400"] } } } entry 20 { from { state ipsec-non-master protocol { name [ipsec] } } action { action-type accept local-preference 70 community { add ["vprn400"] } } } entry 30 { from { state ipsec-master-without-peer protocol { name [ipsec] } } action { action-type accept local-preference 100 community { add ["vprn400"] } } } }
- classic
CLI
A:admin@node-2>config>router>policy-options# info ---------------------------------------------- policy-statement "export400" entry 10 from protocol ipsec state ipsec-master-with-peer exit action accept community add "vprn400" local-preference 255 exit exit entry 20 from protocol ipsec state ipsec-non-master exit action accept community add "vprn400" local-preference 70 exit exit entry 30 from protocol ipsec state ipsec-master-without-peer exit action accept community add "vprn400" local-preference 100 exit exit exit
Shunting configuration on the private side
- MD-CLI
[ex:/configure service vprn "400" ipsec] A:admin@node-2# info multi-chassis-shunt-interface "to84" { next-hop { address 130.100.14.4 } } multi-chassis-shunt-interface "to85" { next-hop { address 130.110.15.5 } } multi-chassis-shunting-profile "shunt1" { peer 84.84.84.84 { multi-chassis-shunt-interface "to84" } peer 85.85.85.85 { multi-chassis-shunt-interface "to85" } } [ex:/configure service vprn "400" interface "priv"] A:admin@node-2# info tunnel true multi-chassis-shunting-profile "shunt1"
- classic
CLI
A:admin@node-2>config>service>vprn>ipsec# info ---------------------------------------------- multi-chassis-shunt-interface "to84" create next-hop 130.100.14.4 exit multi-chassis-shunt-interface "to85" create next-hop 130.110.15.5 exit multi-chassis-shunting-profile "shunt1" create peer 84.84.84.84 create multi-chassis-shunt-interface "to84" exit peer 85.85.85.85 create multi-chassis-shunt-interface "to85" exit exit A:admin@node-2>config>service>vprn# info interface “priv” tunnel create … multi-chassis-shunting-profile "shunt1"
ISA member pool configuration example for DS tunnel-groups
The following example shows an ISA member pool configuration example for DS tunnel-groups. A single ISA 1/2 is shared by two DS tunnel-groups.
- MD-CLI
[ex:/configure isa] A:admin@node-2# info tunnel-group 1 { admin-state enable ipsec-responder-only true multi-active { member-pool "p1" } reassembly { max-wait-time 2000 } } tunnel-group 2 { admin-state enable ipsec-responder-only true multi-active { member-pool "p1" } reassembly { max-wait-time 2000 } } tunnel-member-pool "p1" { isa 1/2 { } }
- classic
CLI
A:admin@node-2>config>isa# info ---------------------------------------------- tunnel-member-pool p1 create mda 1/2 exit tunnel-group 1 create reassembly 2000 ipsec-responder-only multi-active member-pool p1 no shutdown exit tunnel-group 2 create reassembly 2000 ipsec-responder-only multi-active member-pool p1 no shutdown exit
IPsec deployment requirements
The following information describes requirements to deploy SR OS IPsec features.
IPsec general
To avoid high CPU loads and some complex cases, the following are the requirements to configure IKEv2 lifetime:
-
The IKE_SA lifetime on one side should be approximately twice as large as the other side. The CHILD_SA lifetime on one side should be approximately two or three times larger than the other side.
-
With the preceding rule, the lifetime of the side with smaller lifetime should not be too small:
-
IKE_SA: >= 86400 seconds
-
CHILD_SA: >= 3600 seconds
-
-
With first rule, on the side with the smaller lifetime, the IKE_SA lifetime should be at least three times larger than CHILD_SA lifetime.
-
The IKE protocol is the control plane of IPsec, therefore, the IKE packet should be treated as high QoS priority in the end-to-end path of the public service.
On a public interface, a SAP ingress QoS policy should be configured to ensure the IKE packet is treated as high QoS priority.
-
The correct system time is required for certificate authentication to work properly.
-
The peer’s DPD interval must be larger than 30 seconds and should not send a DPD request if it receives IKE or ESP traffic.
MC-IPsec specific
The following are requirements for MC-IPsec specific deployments:
-
The IKEv2 lifetime requirements from IPsec general should be applied with special care to MC-IPsec deployments.
In an MC-IPsec deployment where the MC-IPsec pair peers with single, non-redundant IKE clients, the IKEv2 lifetime requirements must be applied with the larger lifetimes configured on the MC-IPsec pair.
An MC-IPsec deployment where one MC-IPsec pair peers with another MC-IPsec pair is not recommended. MC-IPsec performs optimally when the multichassis pair peers with a single IKE entity. If such a peering (MC-to-MC) is created, the above IKEv2 lifetime requirements should still be followed. However, with one side nominated to be the primary rekey initiator and having the smaller configured lifetimes.
-
Responder-only configuration is a mandatory requirement for all types of tunnels on the MC-IPsec pair in the usual deployment scenario of a MC-IPsec pair peering with single, non-redundant IKE clients.
-
DPD on the peer side (following the DPD requirement in the above IPsec General section). Use the commands in the following context on the MC-IPsec side to configure the DPD interval, the maximum number of retries, and to set the DPD to reply-only.
configure ipsec ike-policy dpd
-
Dedicated, redundant, direct physical link between chassis with enough bandwidth for MCS and shunting traffic.
MIMP/MCS and BFD for MC-IPsec traffic must be forwarded over resilient links so that a single IOM/IMM, MDA or port failure does not cause the MIMP to go down. Because this control traffic is forwarded in the base routing instance, the base routing instance links need to spread over multiple ports on multiple IOM/IMMs. Proper QoS configuration is needed to make sure the control traffic gets the highest priority.
-
A MC-IPsec switchover when the protection status is not nominal may result in unexpected behavior and traffic loss. A nominal state must be reached on both MC-IPsec chassis before a MC-IPsec switchover is triggered.
-
When using VRRP in the public service and a chassis failure occurs, the VRRP/Layer 2 network should re-converge before the MC-IPsec switchover occurs. One way to speed up VRRP switchover is to bind a BFD session to VRRP.
-
The system time of the master and standby chassis must be the same. One way to achieve this is for both chassis to sync to an NTP or SNTP server.
-
The CLI configuration is not synchronized via MCS so the user must provision the same IPsec-related configurations on the master and standby chassis. This includes using the same IKE policy ID, tunnel template ID, public or private interface name, and so on.
-
For an MC-IPsec shunting interface, only one next-hop address is supported; in case of multiple redundant next hops configured using the same shunting interface, the last next hop configured is used.
N:M specific
The following are requirements for N:M-specific deployments.
-
All MC-IPsec specific requirements also apply to N:M.
-
A fully meshed MIMPv2/MCS peering is required between all participating nodes for a specific domain.
-
When adding a node to a domain, ensure that the previous nodes in the domain have fully meshed MIMPv2/MCS peering before adding the new node.
MC-IPsec and N:M specific
-
By default, the configured number of active ISAs (active-isa-number in MD-CLI or active-mda-number in classic CLI) of a tunnel group must be the same on all peering systems. However, if there is a requirement to have a different number of active ISAs on different peering systems, the SPI range index must be configured with a unique value across all peering systems. For example, if N:M domain 1 corresponds to tunnel-group 1 and contains four peering systems, the SPI range index is configured as 1 on system-1 , 2 on system-2, 3 on system-3, and 4 on system-4.
Use the following command to configure the SPI range index.
- MD-CLI
configure isa tunnel-group multi-active spi-range-index
- classic
CLI
configure isa tunnel-group spi-range-index
- MD-CLI
- The spi-range-index must be configured with a unique value across all peering systems when weighted load balancing is configured for the ESA-VMs. See Load-balancing IP tunnels for more information.
Gracefully configuring the SPI range index in an MC-IPsec setup
The spi-range-index command must be configured in a 1:1 or N:M MC-IPsec-enabled tunnel group if any of the following are true:
- for a specific tunnel group, the active-isa-number (active-mda-number in classic CLI) is different on different MC peering systems
- the tunnel group contains ESA-VMs with weight configured
The spi-range-index value ranges from 1 to 4. For a specific tunnel group, a unique value must be configured across all MC peering systems. For example:
- N:M
- tunnel group 1 has three peering systems: A configured with index 1, B with 2, C with 3
- tunnel group 2 has two peering systems: A configured with index 1, B with 2
- 1:1 with two systems, A and B
- tunnel group 1: A configured with index 1, B with 2
- tunnel group 2: A configured with index 2, B with 3
Perform the following procedures to gracefully configure the spi-range-index on a configuration that does not already have it, while minimizing the traffic impact:
Configuring the spi-range-index in a 1:1 setup
Ensure all systems are running SR OS Release 24.10.R1 or later.
Assume two systems, A and B, and the set of tunnel groups that requires the spi-range-index is Q.
-
On system B, ensure every tunnel group of Q is set to standby.
Use the following command to manually switchover the tunnel group to standby when the protection status of the tunnel group is "nominal".
Use the following command to display MC-IPsec tunnel group status information.tools perform redundancy multi-chassis mc-ipsec force-switchover tunnel-group
show redundancy multi-chassis mc-ipsec peer ip-address tunnel-group
- Wait for all tunnel group protection statuses to become "nominal" on both systems.
- Configure the spi-range-index on system B.
- Use the force-switchover tunnel-group command to switchover system B to be active for all tunnel groups.
- Wait for all protection statuses to become "nominal" on both systems.
- Configure the spi-range-index on system A.
- Optional: If there is a requirement to switchover the tunnel groups back to the original MC state, use the force-switchover tunnel-group command only after all tunnel group protection statuses become "nominal".
Configuring the spi-range-index in an N:M setup
Ensure all systems are running SR OS Release 24.10.R1 or later.
Repeat this procedure for each RD with a corresponding tunnel group that requires the spi-range-index configuration.
Assume the RD is R, the corresponding tunnel group is T, and the set of peering systems of R is Q.
-
Ensure the protection status on all systems of Q is "nominal".
Use the following command to display MC-IPsec domain status information.
show redundancy multi-chassis ipsec-domain
- Configure the spi-range-index on all operational standby systems of Q.
- Wait for the protection status on all systems of Q to become "nominal".
-
Assuming the current operational active system is A, use the following command to
switchover system A to standby.
tools perform redundancy multi-chassis mc-ipsec force-switchover domain
- Wait for the protection status on all systems of Q to become "nominal".
- Configure the spi-range-index on A.
- Optional: If there is a requirement to switchover the tunnel groups back to the original MC state, use the force-switchover domain command only after all tunnel group protection statuses become "nominal".
Gracefully modifying the active-isa-number or ESA-VM weight of a tunnel group for IPsec
Perform the following procedures to gracefully modify the active-isa-number (active-mda-number in classic CLI) or ESA-VM weight configuration while minimizing the IPsec traffic impact in a 1:1 or N:M MC-IPsec setup.
Modifying the active-esa-number or ESA-VM weight in a 1:1 setup
- Ensure all systems are running SR OS Release 24.10.R1 or later.
- Ensure the spi-range-index of the tunnel group is configured to a unique value across all MC peering systems.
Repeat this procedure for each system, as required.
Assume the system that needs to be modified is X, and the set of tunnel groups that needs to be modified is S.
-
Ensure every tunnel group of S is set to standby on system X.
Use the following command to manually switchover the tunnel group to standby when the protection status of the tunnel group is "nominal".
Use the following command to display MC-IPsec tunnel group status information.tools perform redundancy multi-chassis mc-ipsec force-switchover tunnel-group
show redundancy multi-chassis mc-ipsec peer ip-address tunnel-group
- Modify the configurations of all tunnel groups of S on system X.
- Wait for all tunnel group protection statuses to become "nominal" on both systems.
- Optional: If there is a requirement to switchover the tunnel groups back to the original MC state, wait for another 60 minutes before performing the switchover using the force-switchover tunnel-group command.
Modifying the active-esa-number or ESA-VM weight in an N:M setup
- Ensure all systems are running SR OS Release 24.10.R1 or later.
- Ensure the spi-range-index of the tunnel group is configured to a unique value across all MC peering systems.
Repeat this procedure for each RD with a corresponding tunnel group that requires modification on some domain’s peering systems.
Assume the RD is R, the corresponding tunnel group is T, the set of peering systems of R is P, and the set of peering systems within P that requires modification is Q.
-
Align the MC statuses:
- If Q < P, ensure that R is the operational standby (OS) on every system of Q.
- If Q = P, select one system S and ensure S is the operational active (OA), while other systems in Q (Q-S) are OS.
If required, use the following command to manually switchover the system.
tools perform redundancy multi-chassis mc-ipsec force-switchover domain
Assume X is every system that was manually switched over to OS.
-
Wait until the protection status becomes "nominal".
Use the following command to display MC-IPsec domain status information.
show redundancy multi-chassis ipsec-domain
-
Modify the configuration of tunnel group T.
-
If Q < P, modify the configuration of T on every system of Q.
-
If Q = P, perform the following steps:
- Modify the configuration of T on every system of Q-S.
- Use the force-switchover domain command to switchover S to OS.
- Wait for the protection status of R to become "nominal" on all systems.
- Wait for another 60 minutes.
- Modify the configuration of T on S.
If the ESA-VM weight needs to be modified on a designated standby system, also modify the weight configuration of T’s tunnel member pool accordingly.
-
- Wait for the protection status of R to become "nominal" on all systems.
- Optional: If there is a requirement to switchover R to its original MC state, wait for another 60 minutes before performing the switchover using the force-switchover domain command.
IKEv2 remote-access tunnel
SR OS supports IKEv2 remote-access tunnel, the difference between a remote-access tunnel and LAN-to-LAN tunnel is remote-access tunnel allows client to request an internal address (and other attributes like DNS address) via IKEv2 configuration payload. The SR OS supports IKEv2 remote-access tunnel with following features:
authentication methods:
pre-shared-key with ) or without RADIUS
certificate with or without RADIUS
EAP or EAP-only with RADIUS
internal address assignment via IKEv2 configuration payload
address assignment support:
RADIUS server based
local address assignment
RADIUS accounting to report address usage
RADIUS disconnect message to remove tunnel
NAT-Traversal support
support MC-IPsec
The SR OS only supports address assignments in first CHILD_SA negotiation.
IKEv2 remote access tunnel – RADIUS-based PSK or certificate authentication
If the authentication method of the IKE policy is psk-radius or cert-radius, then the system authenticates the client using PSK or the certificate as if it is a LAN-to-LAN tunnel. The system also performs a RADIUS authentication or authorization and optionally sends RADIUS accounting messages.
Call flow for RADIUS-based PSK or certificate authentication displays a typical call flow for RADIUS-based PSK or certificate authentication.
The Access-Request includes the following attributes:
-
Username is IDi.
-
User-Password is one of following value’s hash according to section 5.2 of RFC 2865, Remote Authentication Dial In User Service (RADIUS):
-
client’s PSK if psk-radius command option is configured
-
otherwise, a key configured using the password command in the RADIUS authentication policy; if a password is not configured and the system does not include the User-Password attribute in access-request.
-
-
Acct-Session-Id represents the IPsec tunnel session.
The format is: local_gw_ip-remote_ip:remote_port-time_stamp.
For example: 172.16.100.1-192.168.5.100:500-1365016423.
-
Use the following command to configure other RADIUS attributes.
- MD-CLI
configure ipsec radius authentication-policy include-radius-attribute
- classic
CLI
configure ipsec radius-authentication-policy include-radius-attribute
This command configures the following command options.
-
Called-Station-Id (local tunnel address)
-
Calling-station-Id (remote tunnel address:port number)
-
Nas-Identifier (the system name)
-
Nas-Ip-Address (the system IP)
-
Nas-port-id (the public tunnel SAP ID)
- MD-CLI
If RADIUS authentication is successful, then the RADIUS server sends an access-accept message back; otherwise, an access-reject message is sent back.
The following are supported attributes in access-accept:
-
Alc-IPsec-Serv-Id
-
Alc-IPsec-Interface
-
Framed-IP-Address
-
Framed-IP-Netmask
-
Alc-Primary-Dns
-
Alc-Secondary-Dns
-
Alc-IPsec-Tunnel-Template-Id
-
Alc-IPsec-SA-Lifetime
-
Alc-IPsec-SA-PFS-Group
-
Alc-IPsec-SA-Encr-Algorithm
-
Alc-IPsec-SA-Auth-Algorithm
-
Alc-IPsec-SA-Replay-Window
After the tunnel is successfully created, the system could optionally (depending on the configuration of the RADIUS accounting policy configured in the IPsec gateway), send an accounting-start packet to the RADIUS server, and also send an accounting-stop when the tunnel is removed. The user can use the following command to enable this behavior.
- MD-CLI
configure ipsec radius accounting-policy update-interval
- classic
CLI
configure ipsec radius-accounting-policy update-interval
The following are some attributes included in the acct-start/stop and interim-update:
-
Acct-status-type
-
Acct-session-id (the same as in the access-request)
-
Username
Use the following command to configure which RADIUS attributes are included.
- MD-CLI
configure ipsec radius accounting-policy include-radius-attribute
- classic
CLI
configure ipsec radius-accounting-policy include-radius-attribute
This command allows the following command options.
-
Frame-ip-address: the assigned internal address
-
Calling-station-id
-
Called-station-id
-
Nas-Port-Id
-
Nas-Ip-Addr
-
Nas-Identifier
-
Acct-Session-Time (tunnel session time, only in acct-stop packet)
For a complete list of supported attributes, see the 7450 ESS, 7750 SR, and VSR RADIUS Attributes Reference Guide.
The system also supports RADIUS disconnect messages to remove an established tunnel, If the following command is enabled in the RADIUS server configuration, then the system accepts the disconnect-request message (RFC 5176, Dynamic Authorization Extensions to Remote Authentication Dial In User Service (RADIUS)), and tear down the specified remote-access tunnel.
- MD-CLI
configure router radius server accept-coa
- classic
CLI
configure router radius-server server accept-coa
For security reasons, the system only accepts a disconnect-request when accept-coa is configured and the disconnect-request comes from the corresponding server.
The target tunnel is identified by one of following methods:
-
Acct-Session-Id
-
Nas-Port-Id + Framed-Ip-Addr(Framed-Ipv6-Prefix) + Alc-IPsec-Serv-Id
-
User-Name
See the 7450 ESS, 7750 SR, and VSR RADIUS Attributes Reference Guide for more details about disconnect message support.
By default, the system only returns what the client has requested in the CFG_REQUEST payload. However, this behavior can be overridden using the following command.
configure ipsec ike-policy relay-unsolicited-cfg-attribute
With this configuration, the configured attributes returned from the source (such as the RADIUS server) are returned to the client regardless if the client has requested it in the CFG_REQUEST payload.
IKEv2 remote-access tunnel – EAP authentication
The SR OS supports EAP authentication for a IKEv2 remote-access tunnel, in which case, the system acts as an authenticator between an IPsec client and a RADIUS server. It transparently forwards EAP messages between the IKEv2 session and RADIUS session. Thus, the actual EAP authentication occurs between the client and the RADIUS server.
Typical call flow of EAP authentication shows a typical call flow of EAP authentication.
Use the following command option to enable EAP authentication.
- MD-CLI
configure ipsec ike-policy ike-version-2 auth-method eap
- classic
CLI
configure ipsec ike-policy auth-method eap
When enabled, after the received IKE_AUTH request from the client, the system sends an EAP-Response/ID with IDi as the value in the access-request to AAA. AAA returns a method request and the system starts passing through between the client and AAA (as shown in Typical call flow of EAP authentication).
The generation of the AUTH payload in the IKE_AUTH response sent by the SR OS (message 4 in flow shown above) is dependent on the following command.
- MD-CLI
configure ipsec ike-policy ike-version-2 own-auth-method
- classic
CLI
configure ipsec ike-policy own-auth-method
This command allows the following command options.
- psk
- The AUTH payload is present and generated by using PSK.
- cert
- The AUTH payload is present and generated by the configured public and private key pairs as it does in certificate authentication. Any needed certificates are also sent.
- eap-only
- Neither AUTH nor CERT payload is present.
The RADIUS attributes in authentication and accounting packets are similar to psk-radius and cert-radius with the following differences:
-
RADIUS attributes support EAP-Message/Message-Authenticator/State attributes.
-
RADIUS attributes support Access-Challenge packet.
-
RADIUS attributes support MS-MPPE-Send-Key/ MS-MPPE-Recv-Key in access-accept. These two attributes are required for all EAP methods that generate MSK.
The system provides a method to support EAP and other authentication methods on the same IPsec gateway policy. Use one of the following command options to enable the correct authentication method.
- MD-CLI
configure ipsec ike-policy ike-version-2 auth-method auto-eap configure ipsec ike-policy ike-version-2 auth-method auto-eap-radius
- classic
CLI
configure ipsec ike-policy auth-method auto-eap configure ipsec ike-policy auth-method auto-eap-radius
With auto-eap:
-
If there is no AUTH payload in IKE_AUTH request, the system uses EAP to authenticate the client and also uses following command to generate the AUTH payload.
- MD-CLI
configure ipsec ike-policy ike-version-2 own-auth-method
- classic
CLI
configure ipsec ike-policy own-auth-method
- MD-CLI
-
If there is an AUTH payload in the IKE_AUTH request, the authorization method is determined by the following command.
- MD-CLI
configure ipsec ike-policy ike-version-2 auto-eap-method
- classic
CLI
configure ipsec ike-policy auto-eap-method
-
If the auto-eap-method is psk, the system proceeds as auth-method: psk
-
If the auto-eap-method is cert, the system proceeds as auth-method: cert
-
If the auto-eap-method is psk-or-cert:
-
If the Auth Method field of the AUTH payload is PSK, the system proceeds as auth-method: psk
-
If the Auth Method field of the AUTH payload is RSA or DSS, the system proceeds as auth-method: cert-auth
-
- MD-CLI
With auto-eap-radius:
-
If there is no AUTH payload in an IKE_AUTH request, the system uses EAP to authenticate the client and also uses the following command to generate the AUTH payload.
- MD-CLI
configure ipsec ike-policy ike-version-2 own-auth-method
- classic
CLI
configure ipsec ike-policy own-auth-method
- MD-CLI
-
If there is an AUTH payload in the IKE_AUTH request, the system uses the following command to generate the AUTH payload.
- MD-CLI
configure ipsec ike-policy ike-version-2 auto-eap-own-method
- classic
CLI
configure ipsec ike-policy auto-eap-own-method
-
If the auto-eap-own-method is psk, the system proceeds as auth-method: psk-radius
-
If the auto-eap-own-method is cert, the system proceeds as auth-method: cert-radius
-
If auto-eap-own-method is psk-or-cert:
-
If the Auth Method field of the AUTH payload is PSK, the system proceeds as auth-method:psk-radius
-
If the Auth Method field of the AUTH payload is RSA or DSS, the system proceeds as auth-method:cert-radius
-
- MD-CLI
IKEv2 remote-access tunnel – authentication without RADIUS
To achieve authentication without RADIUS, the authentication method needs to be configured as psk or cert-auth and a local address assignment must be configured under the IPsec gateway.
Typical call flow of certificate or PSK authentication without RADIUS shows a typical call flow of certificate or PSK authentication without RADIUS.
Typical call flow for EAP authentication shows a typical call flow for EAP authentication.
In this configuration, the RADIUS authentication and accounting policies in the IPsec gateway context are ignored.
RADIUS disconnect messages are supported in this case. Only the following tunnel identification methods are supported:
Nas-Port-Id + Framed-Ip-Addr(Framed-Ipv6-Prefix) + Alc-IPsec-Serv-Id
User-Name
IKEv2 remote-access tunnel – address assignment
The SR OS supports the following methods of address assignment for IKEv2 remote-access tunnels:
RADIUS
local address assignment (LAA)
DHCPv4/v6
For RADIUS-based address assignment, the address information is returned in an access-accept packet. This implies that RADIUS-based address assignment requires using an authentication option with RADIUS, such as psk-radius, cert-radius, or eap.
For LAA, the system gets an address from a pool defined in a local DHCPv4/v6 server. When a tunnel is removed, the assigned address is released back to the pool. If the local DHCPv4/v6 server is shut down, all existing tunnels that have an address from the server are removed. If LAA is shut down, the current established tunnel that used LAA stays up.
For DHCP-based address assignment, the system acts as a DHCP client on behalf of the IPsec client and requests an address from an external DHCP server via the standard DHCP exchange. In this case, the system also acts as a DHCP relay agent, which relays all DHCP packets between the DHCP server and the local DHCP client. DHCP renew and rebind are also supported.
DHCPv4 address assignment
The client’s hardware address field (chaddr) in the DHCPv4 header is generated by the SR OS:
The first 2 bytes of the MAC address are 02:03.
The remaining 4 bytes are the hash result of IKEv2 IDi.
The following options are included in the DHCPv4 packets sent by the SR OS:
Option 82 circuit-id (private-SAP-id | private-interface-name; for example, tunnel-1.private:100 | priv-int)
Option 82 remote-id (IKEv2 IDi in text format)
Option 61 client-id is 1 byte that represents the IKEv2 IDi type plus the IKEv2 IDi in text format. The value of the first byte is as follows:
ID_IPV4_ADDR = 1
ID_DER_ASN1_DN = 2
ID_FQDN = 3
ID_RFC822_ADDR = 4
ID_IPV6_ADDR = 5
DHCPv6 address assignment
Because the system performs a DHCP relay function, all DHCPv6 packets sent or received are encapsulated in DHCPv6 relay-forward and relay-reply messages.
The following items are values of key fields and options in DHCPv6 packets sent by the system:
Hop-count (0)
Link address (configurable via the CLI)
Peer-address (auto-generated based on the IKEv2 IDi)
Option 1 Client Identifier
DUID type (2)
Enterprise ID (6527)
Value is 1 byte that represents the IKEv2 IDi type plus the IKEv2 IDi in text format. The value of the first byte is the same as that of the first byte in Option 61 for DHCPv4.
Option 16 Vendor Class
Enterprise ID (6527)
Value (string ‟SROS IPsec”)
Option 18 Interface ID (private-SAP-id | private-interface-name; for example, tunnel-1.private:100 | priv-int)
Option 37 Remote Identifier
Enterprise ID (6527)
Value (IKEv2 IDi in text format)
DHCPv4/v6 usage notes
-
Using a local DHCP server on the same chassis for DHCP-based address assignment is not supported. The DHCP server must be external.
-
IPsec DHCP relay uses only the following command gi-address configuration found under the IPsec gateway and does not take into account the gateway IP address with a source IP address configuration on any other interfaces.
- MD-CLI
configure service ies interface sap ipsec-gateway dhcp-address-assignment dhcpv4 gi-address configure service vprn interface sap ipsec-gateway dhcp-address-assignment dhcpv4 gi-address
- classic
CLI
configure service ies interface sap ipsec-gw dhcp gi-address configure service vprn interface sap ipsec-gw dhcp gi-address
- MD-CLI
-
The following command must be enabled on an interface that has a gateway IP address as the interface address for the interface to use a DHCPv4 address assignment. The system ignores other DHCP or DHCPv6 configurations on the interface, with the exception of the relay-proxy configuration.
- MD-CLI
configure service ies interface ipv4 dhcp relay-proxy configure service vprn interface ipv4 dhcp relay-proxy
- classic
CLI
configure service ies interface dhcp relay-proxy configure service vprn interface dhcp relay-proxy
-
If the DHCP server resides in a private service, and the gateway IP address is an address configured on the corresponding tunnel interface, relay-proxy must be enabled on the corresponding private interface.
-
If the DHCP server resides in a routing instance that is different from the private service, then there must be an interface (such as a loopback interface) in the routing instance that has the gateway IP address as the interface address, and gateway IP address must be routable for the DHCP server. Also, the relay proxy must be enabled on the interface in the routing instance.
- MD-CLI
The biggest difference between the LAA and DHCP-based methods is that LAA uses a local API to get an address from a local pool. There is no DHCP packet exchange for LAA, while a DHCP-based method uses standard DHCP packet exchange to request a packet from an external DHCP server.
Because there are three methods for address assignment, the following is the priority order (descending) of sources to choose if more than one source is configured:
LAA
DHCP
RADIUS
There is no fallback between the different sources.
LAA/DHCP can work with an authentication method that does not involve RADIUS, as well as with an authentication method that involves RADIUS. When using LAA/DHCP with an authentication method that involves RADIUS, the following applies:
LAA/DHCP only happens after RADIUS is successfully authenticated.
The address information returned by the RADIUS server is ignored (even if LAA/DHCP is configured but is shut down).
Non-address-related attributes in access-accept messages such as Alc-IPsec-Serv-Id and Alc-IPsec-Tunnel-Template-Id are still accepted.
RADIUS accounting is supported in this case, but the Framed-IP-Addr/Framed-IPv6-Prefix reported in the acct-request packet is the LAA/DHCP assigned address, not the address returned by the RADIUS server.
RADIUS disconnect messages are supported.
For MC-IPsec:
-
With LAA, the configuration of the following command is not needed. This is because the assigned address is synchronized as part of the IPsec tunnel states.
configure redundancy multi-chassis peer sync local-dhcp-server
-
Consider the following about DHCP:
-
The DHCP packet exchange process only occurs on the master chassis.
-
The assigned address is synchronized to the standby chassis as part of the IPsec states. The standby chassis does not initiate any DHCP exchanges.
-
The DHCP server address configured using the following command should be the same on both chassis.
- MD-CLI
configure service ies interface sap ipsec-gateway dhcp-address-assignment dhcpv4 server address configure service vprn interface sap ipsec-gateway dhcp-address-assignment dhcpv4 server address
- classic
CLI
configure service ies interface sap ipsec-gw dhcp server configure service vprn interface sap ipsec-gw dhcp server
- MD-CLI
-
After an MC switchover:
-
The new master does not initiate any DHCP process unless it is time to renew an address or a tunnel goes down.
-
If a new master needs to renew an address or release an address, it sends the DHCP packet to the same DHCP server address that assigned the address on the old master, assuming the external DHCP server is still on, and the renew or release is processed normally.
-
If the new master needs to assign an address for a new tunnel setup, it sends a DHCP discovery or solicit message to all configured DHCP server addresses and then pick the first offer or advertise to finish the DHCP process.
-
-
For DHCPv4, a gateway IP address is used by the server to forward a response back, so the gateway IP address must be an interface address of the router. For multichassis operation, if a DHCPv4 server resides in a private VPRN, there are two options:
-
Configure the same private interface address on both chassis and then use it as the gateway IP address. Configure MC-IPsec-aware routing to make sure that the DHCP response is directed to the master.
-
Configure different private interface addresses with the same subnet on both chassis. The gateway IP address is the private interface address of the local chassis. As well as the private subnet, two /32 private interface address routes from two chassis also need to be advertised so that the DHCP response is routed to the correct chassis.
If the DHCPv4 server does not reside in a private VPRN, then one method is to configure a loopback interface with a /32 address in the private subnet, and the loopback interface address is used as the gateway IP address. Different addresses must be configured on the master and standby chassis.
-
-
For DHCPv6, unlike DHCPv4, the link-address is not used for the server to forward responses back. The DHCPv6 server sends responses to the source address of the request. This typically is the egress interface address when the system sends out the relay-forward message. For MC-IPsec, no special configuration is required as long as the DHCPv6 server can route relay-reply messages back to the correct chassis.
-
IPv6 IPsec support
The SR OS provides the following IPv6 support to IPsec functions:
IPv6 packets as the ESP tunnel payload
IPv6 as the ESP tunnel encapsulation
IPv6 as payload
IPv6 as payload allows IPv6 packets to be forwarded within an IPsec tunnel. Current support includes the following:
Tunnel type support includes:
static LAN-to-LAN tunnel
dynamic LAN-to-LAN tunnel
remote-access tunnel (only IKEv2 is supported)
The prefix length of the IPv6 address on a private interface must be /96 or longer.
IPv6 as payload: static LAN-to-LAN tunnel
There are three methods to forward IPv6 traffic into static tunnels on the private side:
-
The destination address is a configured destination IP under the tunnel context.
-
The destination IP can be either an IPv6 address or an IPv4 address.
-
In the case of IPv6, it must be either an IPv6 global unicast address or an IPv6 link-local address.
-
In the case of IPv4, it can be used to forward IPv4 traffic into the tunnel.
-
In case of unicast address, dest-ip must be within the prefix configured on the private interface.
-
Up to 16 destination IP addresses can be configured per IPsec tunnel.
-
-
A v6 route with a configured destination IP as the next-hop, this route can be learned from either a static or dynamic from a routing protocol such as BGP.
-
An IPv6 static route with an ipsec-tunnel used as the next-hop.
A security policy supports either an IPv4 entry or an IPv6 entry or both for dual-stack.
IPv6 as payload: dynamic LAN-to-LAN tunnel
With dynamic LAN-to-LAN tunnels, the system automatically creates a v6 reverse route in the private VPRN based on the received TSi payload with the tunnel as the next hop.
IPv6 as payload: remote-access tunnel
The system supports the following IKEv2 IPv6 configuration attributes:
INTERNAL_IP6_ADDRESS
INTERNAL_IP6_DNS
The system supports only one internal IPv6 address per tunnel. The following IPv6-related RADIUS attributes are also supported in access-accept:
Framed-IPv6-Prefix is translated into INTERNAL_IP6_ADDRESS in the configuration payload, which includes two parts. A 16-byte v6 prefix and a one-byte prefix length.
Alc-Ipv6-Primary-Dns
Alc-Ipv6-Secondary-Dns
If an internal v6 address has been assigned to the remote-access client, then the Framed-IPv6-Prefix is also included in RADIUS accounting-request packet. The assigned internal v6 address must be within the prefix configured on the corresponding private interface.
If the client request both v4 and v6 address and address source (such as RADIUS or LAA) assign both v4 and v6 address, then both v4 and v6 addresses are assigned to the client via the configuration payload.
IPv6 as encapsulation
IPv6 as encapsulation allows IPv4 or IPv6 packets to be forwarded within an IPv6 ESP tunnel, also the IKE protocol can run over IPv6. Current support only includes tunnel type support:
-
static LAN-to-LAN tunnel
-
dynamic LAN-to-LAN tunnel
-
remote-access tunnel (For IKEv1, only v4 over v6 is supported)
For an ipsec-gw or ipsec-tunnel, only one local gateway address is supported, which could be either an IPv4 or IPv6 address. The SR OS also provides fragmentation and reassembly support for IPv6 ESP/IKE packets.
MLDv2 over IPsec
The system supports replicating IPv6 multicast traffic into IKEv2 IPsec tunnels based on the MLDv2 report received from the IPsec client.
If a client needs to receive IPv6 multicast traffic over an IPsec tunnel, it includes corresponding multicast address ranges in the traffic selector during CHILD_SA negotiation. After the CHILD_SA is created, the client sends an MLDv2 report to join specific multicast groups over the CHILD_SA. The SeGW terminates the MLDv2 report message and begins replicating requested multicast traffic into the CHILD_SA.
Internally, the system treats each multicast-enabled CHILD_SA as an MLD interface called ipsec-interface in various multicast show commands.
This feature supports only IPv6 multicast with MLDv2 and Source Specific Multicast (SSM).
This feature supports only IKEv2 tunnels. For IKEv2 static tunnel, this feature only supports a single child SA per tunnel for multicast traffic.
MLDv2 over IPsec – traffic selector
The negotiated traffic selector of CHILD_SA that transports IPv6 multicast traffic must include the following address ranges:
an address range for MLDv2 traffic
an address range for multicast source (IPv6 global unicast address)
an address range for expected multicast group
The following is an example of a traffic selector of a CHILD_SA that only carries multicast traffic:
-
TSi
-
FF02::1/128 # destination address of the MLDv2 generic query packet
-
FE80::/64 # IPv6 link local address range, source address of the MLDv2 report packet
-
FF3E::/32 # IPv6 multicast address range, global scope. This is for multicast data traffic and MLDv2 (S,G) specific query
-
-
TSr
-
multicast source address range (global unicast)
-
FF02::16/128 # destination address of the MLDv2 report packet
-
FE80::/64 #source address of the MLDv2 query packet
-
MLDv2 over IPsec – configuration
MLDv2 over IPsec is enabled by adding private IPsec interface in MLD configuration. The following example configures MLDv2 over IPsec.
The MLD configuration under the private interface level is ignored by the system.
MD-CLI
[ex:/configure service vprn "1"]
A:admin@node-2# info
customer "27"
mld {
interface "priv" {
admin-state enable
}
}
interface "priv" {
tunnel true
sap tunnel-1.private:200 {
}
ipv6 {
address 2001:dead::1 {
prefix-length 96
}
}
}
classic CLI
A:node-2>config>service>vprn# info
----------------------------------------------
mld
interface "priv"
no shutdown
exit
no shutdown
exit
interface "priv" tunnel create
ipv6
address 2001:dead::1/96
exit
sap tunnel-1.private:200 create
exit
exit
----------------------------------------------
Secured interface
A secured interface secures traffic forwarded through a specified IP interface, through one or multiple Secure Interface Tunnels (SI Tunnels) configured under the interface. SI tunnel is conceptually the same as traditional static IPsec tunnels. Some differences are:
SI tunnels are configured under an IP interface, while static IPsec tunnels are configured under the private tunnel SAP of a tunnel interface.
With an SI tunnel, the following objects are created automatically with an SI tunnel configuration. There is no need for a separate configuration tunnel configuration:
public tunnel SAP
public interface
private tunnel SAP
private tunnel interface
The public service of SI tunnel is the same service of secured interface, which could be either base router, an IES or an VPRN service.
The local tunnel address of the SI tunnel must be one of interface addresses of the secure interface. If the secure interface is unnumbered, then it must be one of the interface address of the interface specified by the unnumbered configuration.
Private service is the same as the public service. The user could also specify a different service.
On the public side:
-
With a secured interface, by default, all traffic ingress the interface are subject to IPsec processing. If the received traffic is not IPsec traffic (such as ESP and IKE), it is dropped. Use the following commands to change this behavior.
configure filter ip-exception configure filter ipv6-exception
All ingress traffic matching the configured exception filter bypasses IPsec processing and is forwarded through normal routing methods.
The system forwards all SI tunnel traffic (after encryption and encapsulation) out through the corresponding secured interface.
SSH traffic toward the local system and MPLS/SDP always bypasses IPsec processing.
-
On the private side:
Like a static IPsec tunnel, traffic is routed into the SI tunnel through a static route or BGP route.
When an SI tunnel is operationally down, routes using the next-hop address as the tunnel are unresolved and withdrawn from the route table.
show, debug, tool, clear, and admin commands that apply to static IPsec tunnels also apply to SI tunnels.
The following features are not supported with SI tunnels on 7705 SAR-Hm (with cellular exit port):
destination IP
MC-IPsec
IPv4 over IPv6
IPv6 over IPv6
MLDv2 over SI tunnel
The following features are not supported with SI tunnels on VSR:
destination IP
MC-IPsec
MLDv2 over SI tunnel
SI tunnel are only supported in VSR and 7705 SAR-Hm families.
IPsec client database
Use the following command to configure the IPsec client database, which can be used to authenticate and authorize IKEv2 dynamic LAN-to-LAN tunnels.
configure ipsec client-db
Each client database contains one or more client entries. When the system receives a new tunnel request, it performs a look up in the associated database of the IPsec gateway. If there is match, the system optionally could use credentials configured in the matched client entry to authenticate the peer. If the authentication succeeds, then, optionally, the matched entry could also return specific IPsec parameters such as the private service ID which can be used for tunnel setup.
If the client database lookup failed to return a match result, then the system can either fall back to the IPsec gateway level configuration or fail the tunnel setup. The action to take depends on the CLI configuration.
The system supports one of the following as matching input:
-
the peer’s tunnel IP address
-
the peer’s IDi
-
a combination of both
The above matching input is defined in the following context.
configure ipsec client-db match-list
Each client entry contains client matching criteria that corresponds to the match list. The system correlates matching input with the client matching criteria of each client entry in the client-db configuration. The system supports the following matching methods:
-
for the peer IDi
-
Any matches any IDi.
-
IPv4/IPv6 prefix matches the peer address type IDi to a configured prefix. It is considered a match if the IDi falls within the prefix.
-
FQDN matches the peer FQDN type IDi to a string. This supports a complete string match or a suffix string match.
-
RFC822 matches the peer RFC 822 type IDi to a string. This supports a complete string match or suffix string match.
-
-
for the peer tunnel IP address
-
Matches the peer tunnel address to a configured prefix. It is a match if the IDi fall within the prefix.
-
IPv4 Any matches any IPv4 address.
-
IPv6 Any matches any IPv6 address.
-
Each client entry has a client index (an integer). This is different from a client identification. If there are multiple matched entries in a lookup, the client entry with the smallest client index is used. The client entry supports using a pre-shared key as the credential.
If the credential is not configured in the matched entry, the credential configured under the IPsec gateway is used.
A client entry could optionally return the following IPsec parameters:
-
a private service ID
-
a private interface name
-
a tunnel-template ID
-
a Ts list
The returned parameter overrides the configuration of the IPsec gateway level.
There is only one client-db for each IPsec gateway, but different IPsec gateway configurations can use the same client-db.
Note that the encapsulated IP MTU in the client database-returned tunnel-template is not applied to the IKE packet fragmentation. The value configured by the following command is used instead. However, the client database-returned encapsulated IP MTU value still applies to the ESP packet fragmentation.
configure ipsec tunnel-template encapsulated-ip-mtu
-
A client entry in an administratively disabled state is skipped while the system performs the matching process.
-
If the configuration returned by client-db is invalid, the system fails the tunnel setup.
-
The reference of the client-db under the IPsec gateway can be changed without shutting down the IPsec gateway.
-
Shutting down a referenced client-db without shutting down IPsec gateway is allowed and the established tunnel is not impacted. The system uses the configuration on the IPsec gateway level for new a tunnel request while the client-db is administratively disabled if a fallback is configured.
-
Adding a new client in a referenced client-db without shutting down IPsec gateway or client-db is allowed.
-
Removing a client in the referenced client-db without shutting down IPsec gateway or client-db is allowed. However, the administrative disabling of the client to be removed is required.
-
Changing an existing client of a referenced client-db without shutting down IPsec gateway or client-db is allowed. However, the administrative disabling of the client to be removed is required.
IPsec transport mode protected IP tunnel
Tunnel-group based GRE tunnels can be protected by applying IPsec transport mode encryption for the GRE tunnel packets. This is achieved by configuring an IPsec transport mode profile under the IP tunnel configuration. When the profile is enabled, the datapath flow as follows in the private to public direction:
The payload packet is received on the private tunnel SAP.
-
Optionally perform pre-encapsulation fragmentation based on the payload packet size and the following command configurations.
configure service ies interface sap ip-tunnel configure service vprn interface sap ip-tunnel
The payload packet is encapsulated into a GRE tunnel packet.
The IPsec transport mode encryption is applied on the GRE tunnel packet which results in an IPsec ESP packet.
-
Optionally, perform post-encapsulation fragmentation based on the ESP packet size and the configured encapsulated IP MTU configured by the following commands.
configure service ies interface sap ip-tunnel encapsulated-ip-mtu configure service vprn interface sap ip-tunnel encapsulated-ip-mtu
In the public to private direction, the datapath flows as follows:
-
The IPsec ESP packet is received on the public tunnel SAP.
-
ESP packet reassembly is performed if it is fragmented.
-
The ESP packet is decrypted, which results as a GRE tunnel packet.
-
The GRE tunnel packet is decapsulated and the payload packet is forwarded out of the private tunnel SAP.
This feature uses IKEv2 to create an IKE_SA and a transport mode CHILD_SA for a specific GRE tunnel. The IKE/IPsec behaves similarly to an IPsec static LAN-to-LAN tunnel, with some transport-mode specific differences.
Packet format
The packet format of GRE with IPsec transport mode follows RFC 4303, IP Encapsulating Security Payload (ESP), Section 3.1.1. The following example shows an IPv4 GRE packet with IPsec transport mode enabled:
The following example shows an IPv6 GRE packet with IPsec transport mode enabled:
IKEv2 and SA
This feature only requires a single IKE_SA and CHILD_SA per GRE tunnel. Additional CHILD_SA creation requests from a CREATE_CHILD_SA peer exchange are rejected.
This feature uses IKEv2 USE_TRANSPORT_MODE notification to signal the use of the transport mode when the CHILD_SA is created. The system expects the notification to be included in both the request and response messages.
Traffic selector
As a CHILD_SA initiator, the traffic selector is proposed as follows:
address range (the source and destination GRE tunnel endpoint address, /32 or /128)
protocol (GRE)
port range (0 to 65535)
As a CHILD_SA responder, the system uses the same traffic selector to narrow the selection peer’s proposal.
Fragmentation and reassembly
ISA only fragments packets in the private to public direction. The following two types of fragmentation are used.
-
Use the following command to control fragmentation before GRE encapsulation.
configure service ies interface sap ip-tunnel ip-mtu configure service vprn interface sap ip-tunnel ip-mtu
-
Use the following command to control the fragmentation after IPsec processing.
configure service ies interface sap ip-tunnel encapsulated-ip-mtu configure service vprn interface sap ip-tunnel encapsulated-ip-mtu
ISA only reassembles received ESP packets on the public side before IPsec decryption. Use the following command to control the reassembly behavior.
configure isa tunnel-group reassembly
QoS marking
QoS marking refers to the Type of Service field in IPv4 header or the Traffic Class field in the IPv6 header.
behavior in the private to the public direction
If DSCP is configured under the IP tunnel, the configured value is used for the QoS marking in the GRE IP header. If DSCP is not configured, then the payload packet’s QoS marking is copied into the GRE IP header.
-
behavior in the public to private direction
The received ESP packet is decrypted, and as a result, the GRE packet is decapsulated into a payload packet. The QoS marking of the original payload packet is preserved.
Configuring IPsec transport mode protected tunnels
For IPsec transport mode protected tunnels, include the following:
-
a GRE tunnel
-
IPsec parameters:
-
IKE policy
-
IKE transform
-
IPsec transform
-
certificate or trust-anchor profile (if certificate authentication is required)
-
IPsec transport mode profile referenced under the GRE tunnel
-
The following examples show IPsec transport mode protected tunnel configurations.
MD-CLI
[ex:/configure ipsec]
A:admin@node-2# info
ike-policy 1 {
ike-transform [1]
ike-version-2 {
}
}
ike-transform 1 {
dh-group group-20
ike-auth-algorithm auth-encryption
ike-encryption-algorithm aes256-gcm16
ike-prf-algorithm sha-384
}
ipsec-transform 1 {
esp-auth-algorithm auth-encryption
esp-encryption-algorithm aes256-gcm16
pfs-dh-group group-20
}
ipsec-transport-mode-profile "test" {
key-exchange {
dynamic {
ike-policy 1
ipsec-transform [1]
pre-shared-key "KrbVPnF6Dg13PM/biw6ErPl5XU7+ hash2"
}
}
}
[ex:/configure service vprn "1"]
A:admin@node-2# info
customer "27"
interface "priv" {
tunnel true
ipv4 {
addresses {
address 44.44.44.1 {
prefix-length 24
}
}
}
sap tunnel-1.private:100 {
ip-tunnel "t1" {
delivery-service "testds"
remote-ip-address 192.168.1.2
local-ip-address 172.16.100.1
ipsec-transport-mode-profile "test"
gre-header {
admin-state enable
}
dest-ip 44.44.44.2 { }
}
}
}
interface "test" {
sap 1/2/3:0 {
}
}
classic CLI
A:node-2>config>ipsec# info
----------------------------------------------
ike-transform 1 create
dh-group 20
ike-auth-algorithm auth-encryption
ike-encryption-algorithm aes256-gcm16
ike-prf-algorithm sha384
exit
ike-policy 1 create
ike-version 2
ike-transform 1
exit
ipsec-transform 1 create
esp-auth-algorithm auth-encryption
esp-encryption-algorithm aes256-gcm16
pfs-dh-group 20
exit
ipsec-transport-mode-profile "test" create
dynamic-keying
ike-policy 1
pre-shared-key "KrbVPnF6Dg13PM/biw6ErPl5XU7+" hash2
transform 1
exit
exit
A:node-2>config>service>vprn# info
----------------------------------------------
interface "priv" tunnel create
address 44.44.44.1/24
sap tunnel-1.private:100 create
ip-tunnel "t1" create
dest-ip 44.44.44.2
gre-header
source 172.16.100.1
remote-ip 192.168.1.2
delivery-service name testds
ipsec-transport-mode-profile "test"
no shutdown
exit
exit
exit
Configuring IPsec with CLI
Provisioning a tunnel ISA
The following example displays a card and ISA configuration.
MD-CLI
[ex:/configure]
A:admin@node-2# info
card 1 {
card-type iom4-e
mda 1 {
mda-type me40-1gb-csfp
}
mda 2 {
mda-type isa2-tunnel
}
classic CLI
A:node-2>config# info
----------------------------------------------
...
card 1
card-type iom4-e
mda 1
mda-type me40-1gb-csfp
no shutdown
exit
mda 2
mda-type isa2-tunnel
no shutdown
exit
no shutdown
...
----------------------------------------------
Configuring a tunnel group
The following example displays a tunnel group configuration in the ISA context. The multi-active command specifies that there could be multiple active ISAs in the tunnel group.
MD-CLI
[ex:/configure]
A:admin@node-2# info
isa {
tunnel-group 1 {
admin-state enable
isa-scale-mode tunnel-limit-2k
multi-active {
isa 1/2 { }
}
}
}
classic CLI
A:node-2>config# info
----------------------------------------------
...
isa
tunnel-group 1 isa-scale-mode tunnel-limit-2k create
multi-active
mda 1/2
no shutdown
exit
exit
...
----------------------------------------------
Configuring router interfaces for IPsec
The following example displays an interface named ‟internet” that is configured using the network port (1/1/1), which provides network connection on the public side.
MD-CLI
[ex:/configure router "Base"]
A:admin@node-2# info
autonomous-system 123
interface "internet" {
port 1/1/1
ipv4 {
primary {
address 10.10.7.118
prefix-length 24
}
}
}
interface "system" {
ipv4 {
primary {
address 10.20.1.118
prefix-length 32
}
}
}
classic CLI
A:node-2>config# info
----------------------------------------------
...
router Base
interface "internet"
address 10.10.7.118/24
port 1/1/1
no shutdown
exit
interface "system"
address 10.20.1.118/32
no shutdown
exit
autonomous-system 123
...
----------------------------------------------
Configuring IPsec command options
The following example displays an IPsec configuration.
MD-CLI
[ex:/configure ipsec]
A:admin@node-2# info
ike-policy 100 {
ike-transform [100]
ike-version-2 {
auth-method eap
}
}
ike-transform 100 {
dh-group group-14
ike-auth-algorithm sha-256
isakmp-lifetime 90000
}
classic CLI
A:node-2>config>ipsec# info
----------------------------------------------
ike-transform 100 create
dh-group 14
ike-auth-algorithm sha256
isakmp-lifetime 90000
exit
ike-policy 100 create
ike-version 2
auth-method eap
ike-transform 100
exit
----------------------------------------------
Configuring IPsec in services
The following example displays an IES and VPRN service with IPsec command options configured.
MD-CLI
[ex:/configure service]
A:admin@node-2# info
ies "100" {
admin-state enable
customer "1"
interface "ipsec-public" {
sap tunnel-1.public:1 {
}
ipv4 {
primary {
address 10.10.10.1
prefix-length 24
}
}
}
}
vprn "200" {
admin-state enable
customer "1"
ipsec {
security-policy 1 {
entry 1 {
local-ip {
address 172.16.118.0/24
}
remote-ip {
address 172.16.91.0/24
}
}
}
}
bgp-ipvpn {
mpls {
admin-state enable
route-distinguisher "1:1"
}
}
interface "corporate-network" {
ipv4 {
primary {
address 172.16.118.118
prefix-length 24
}
}
sap 1/1/2 {
}
}
interface "ipsec-private" {
tunnel true
sap tunnel-1.private:1 {
ipsec-tunnel "remote-office" {
key-exchange {
dynamic {
ike-policy 1
ipsec-transform [1]
pre-shared-key "0PuXIi3wAoMOkSffbuDDViSy4jnc4N2vRrT1Qw== hash2"
}
}
tunnel-endpoint {
local-gateway-address 10.10.10.118
remote-ip-address 10.10.7.91
delivery-service "delivery"
}
security-policy {
id 1
}
}
}
static-routes {
route 172.16.91.0/24 route-type unicast {
ipsec-tunnel "t1" {
admin-state enable
}
}
classic CLI
A:node-2>config# info
----------------------------------------------
...
service
ies 100 name "100" customer 1 create
interface "ipsec-public" create
address 10.10.10.1/24
tos-marking-state untrusted
sap tunnel-1.public:1 create
exit
exit
no shutdown
exit
vprn 200 customer 1 create
ipsec
security-policy 1 create
entry 1 create
local-ip 172.16.118.0/24
remote-ip 172.16.91.0/24
exit
exit
exit
route-distinguisher 1:1
interface "ipsec-private" tunnel create
sap tunnel-1.private:1 create
ipsec-tunnel "remote-office" create
security-policy 1
local-gateway-address 10.10.10.118 peer 10.10.7.91 delivery-service-name delivery
dynamic-keying
ike-policy 1
pre-shared-key "humptydumpty"
transform 1
exit
no shutdown
exit
exit
exit
interface "corporate-network" create
address 172.16.118.118/24
sap 1/1/2 create
exit
exit
static-route-entry 172.16.91.0/24
ipsec-tunnel "t1"
no shutdown
exit
exit
no shutdown
exit
exit
...
----------------------------------------------
Configuring X.509v3 certificate command options
The following are steps to configure certificate enrollment:
-
Generate a key.
- MD-CLI
admin system security pki generate-keypair cf3:/key_plain_rsa2048 admin system security pki generate-keypair rsa-key-size 2048
- classic
CLI
admin certificate gen-keypair cf3:/key_plain_rsa2048 size 2048 type rsa
- MD-CLI
-
Generate a certificate request.
- MD-CLI
admin system security pki generate-csr key-url cf3:/key_plain_rsa2048 output-url cf3:/7750-req.cs subject-dn "C=US,ST=CA,CN=7750"
- classic
CLI
admin certificate gen-local-cert-req keypair cf3:/key_plain_rsa2048 subject- dn "C=US,ST=CA,CN=7750" file 7750_req.cs
- MD-CLI
-
Send the certificate request to CA-1 to sign and get the signed certificate.
-
Import the key.
- MD-CLI
admin system security pki import type key input-url cf3:/key_plain_rs2048 output-file key1_rsa2048 format der
- classic
CLI
admin certificate import type key input cf3:/key_plain_rsa2048 output key1_rsa2048 format der
- MD-CLI
-
Import the signed certificate.
- MD-CLI
admin system security pki import type cert input-url cf3:/7750_cert.pem output-file 7750cert format pem
- classic
CLI
admin certificate import type cert input cf3:/7750_cert.pem output 7750cert format pem
- MD-CLI
The following are steps to configure CA certificate/CRL import.
-
Import the CA certificate.
- MD-CLI
admin system security pki import type certificate input-url cf3:/CA_1_cert.pem output-file ca_cert format pem
- classic
CLI
admin certificate import type cert input cf3:/CA_1_cert.pem output ca_cert format pem
- MD-CLI
-
Import the CA’s CRL.
- MD-CLI
admin system security pki import type certificate input-url cf3:/CA_1_crl.pem output-file ca_crl format pem
- classic
CLI
admin certificate import type crl input cf3:/CA_1_crl.pem output ca_crl format pem
- MD-CLI
The following example displays a certificate authentication for IKEv2 static LAN-to-LAN tunnel configuration.
MD-CLI
[ex:/configure system security pki]
A:admin@node-2# info
ca-profile "NOKIA-root" {
admin-state enable
cert-file "NOKIA_root.cert"
crl-file "NOKIA_root.crl"
}
[ex:/configure ipsec]
A:admin@node-2# info
cert-profile "segw" {
admin-state enable
entry 1 {
cert "segw.cert"
key "segw.key"
}
}
ike-policy 1 {
ike-transform [1]
ike-version-2 {
auth-method cert
}
}
ike-transform 1 {
}
ipsec-transform 1 {
}
trust-anchor-profile "nokia" {
trust-anchor "NOKIA-root" { }
}
[ex:/configure service vprn "200" interface "ipsec-private" sap tunnel-1.private:1]
A:admin@node-2# info
ipsec-tunnel "t50" {
admin-state enable
key-exchange {
dynamic {
ike-policy 1
ipsec-transform [1]
cert {
cert-profile "segw"
trust-anchor-profile "nokia"
}
}
}
tunnel-endpoint {
local-gateway-address 192.168.55.30
remote-ip-address 192.168.33.100
delivery-service "delivery"
}
security-policy {
id 1
}
}
classic CLI
A:node-2>config>system>security>pki# info
----------------------------------------------
ca-profile "NOKIA-root" create
cert-file "NOKIA_root.cert"
crl-file "NOKIA_root.crl"
no shutdown
exit
----------------------------------------------
A:node-2>config>ipsec# info
----------------------------------------------
ike-policy 1 create
ike-version 2
auth-method cert-auth
ike-transform 1
exit
ipsec-transform 1 create
exit
ike-transform 1 create
exit
cert-profile "segw" create
entry 1 create
cert segw.cert
key segw.key
exit
no shutdown
exit
trust-anchor-profile "nokia" create
trust-anchor "nokia-root"
exit
----------------------------------------------
A:node-2>config>service>vprn>if>sap
----------------------------------------------
ipsec-tunnel "t50" create
security-policy 1
local-gateway-address 192.168.55.30 peer 192.168.33.100 delivery-service delivery
dynamic-keying
ike-policy 1
transform 1
cert
trust-anchor-profile "nokia"
cert-profile "segw"
exit
exit
no shutdown
exit
Configuring MC-IPsec
Configuring MIMP
The peer’s tunnel-group ID is not necessarily the same as the local tunnel-group ID. With BFD enabled, the BFD command options are specified under the interface that the MIMP source address resides on, which must be a loopback interface in the base routing instance. The default source address of MIMP is the system address.
The following commands define the MIMP alive command option, however, BFD could be used for faster chassis failure detection.
configure redundancy multi-chassis peer mc-ipsec keep-alive-interval
configure redundancy multi-chassis peer mc-ipsec hold-on-neighbor-failure
The SR OS also provides the following tools command to manually trigger the switchover.
tools perform redundancy multi-chassis mc-ipsec force-switchover tunnel-group
The following example shows an MIMP configuration.
MD-CLI
[ex:/configure redundancy multi-chassis]
A:admin@node-2# info
peer 10.2.2.2 {
admin-state enable
mc-ipsec {
bfd-liveness true
tunnel-group 1 {
admin-state enable
peer-group 2
priority 120
}
}
}
classic CLI
A:node-2>config>redundancy>multi-chassis
----------------------------------------------
peer 10.2.2.2 create
mc-ipsec
bfd-enable
tunnel-group 1 create
peer-group 2
priority 120
no shutdown
exit
exit
no shutdown
exit
Configuring multichassis synchronization
The following example displays an MCS for MC-IPsec configuration.
MCS for MC-IPsec configuration (MD-CLI)
[ex:/configure redundancy multi-chassis]
A:admin@node-2# info
peer 10.2.2.2 {
sync {
admin-state enable
ipsec true
tunnel-group 1 {
sync-tag "sync_tag_1"
}
}
}
MCS for MC-IPsec configuration (classic CLI)
A:node-2>config>redundancy>multi-chassis>
----------------------------------------------
peer 10.2.2.2 create
sync
ipsec
tunnel-group 1 sync-tag "sync_tag_1" create
no shutdown
exit
The following example displays an MCS for MC-IPsec configuration with MCS encryption enabled.
The sync-tag must match on both chassis for the corresponding tunnel groups.
MCS for MC-IPsec configuration with MCS encryption enabled (MD-CLI)
[ex:/configure redundancy multi-chassis]
A:admin@node-2# info
peer 10.20.1.2 {
admin-state enable
source-address 10.20.1.1
sync {
admin-state enable
ipsec true
transport-encryption {
application ipsec {
keychain "validMultiBi"
}
}
tunnel-group 1 {
sync-tag "ipsec-t-grp-1"
}
}
mc-ipsec {
bfd-liveness true
tunnel-group 1 {
admin-state enable
peer-group 1
priority 255
}
}
}
MCS for MC-IPsec configuration with MCS encryption enabled (classic CLI)
A:node-2>config>redundancy>multi-chassis
peer 10.20.1.2 create
source-address 10.20.1.1
sync
ipsec
tunnel-group 1 sync-tag "ipsec-t-grp-1" create
transport-encryption
application "ipsec" keychain "validMultiBi"
exit
exit
no shutdown
exit
mc-ipsec
bfd-enable
tunnel-group 1 create
peer-group 1
priority 255
no shutdown
exit
exit
no shutdown
exit
exit
----------------------------------------------
Configuring routing for MC-IPsec
The following example displays a configuration using a route policy to export the /32 local tunnel address route.
MD-CLI
[ex:/configure policy-options]
A:admin@node-2# info
policy-statement "exportOSPF" {
entry 10 {
from {
state ipsec-master-with-peer
protocol {
name [ipsec]
}
}
action {
action-type accept
metric {
set 500
}
}
}
entry 20 {
from {
state ipsec-non-master
protocol {
name [ipsec]
}
}
action {
action-type accept
metric {
set 1000
}
}
}
entry 30 {
from {
state ipsec-master-without-peer
protocol {
name [ipsec]
}
}
action {
action-type accept
metric {
set 1000
}
}
}
}
classic CLI
A:node-2>config>router>policy-options>
----------------------------------------------
policy-statement "exportOSPF"
entry 10
from
protocol ipsec
state ipsec-master-with-peer
exit
action accept
metric set 500
exit
exit
entry 20
from
protocol ipsec
state ipsec-non-master
exit
action accept
metric set 1000
exit
exit
entry 30
from
protocol ipsec
state ipsec-master-without-peer
exit
action accept
metric set 1000
exit
exit
exit
Shunting is enabled by configuring a redundant next-hop on a public or private IPsec interface for a static or dynamic tunnel.
The following examples show shunting in public and private services.
Shunting in public service (MD-CLI)
[ex:/configure service ies "2"]
A:admin@node-2# info
interface "ipsec-pub" {
static-tunnel-redundant-nexthop 10.1.1.1
sap tunnel-1.public:100 {
}
ipv4 {
primary {
address 172.16.100.254
prefix-length 24
}
}
}
Shunting in public service (classic CLI)
A:node-2>config>service>ies>
interface "ipsec-pub" create
address 172.16.100.254/24
sap tunnel-1.public:100 create
exit
static-tunnel-redundant-next-hop 10.1.1.1
exit
Shunting in private service (MD-CLI)
[ex:/configure service vprn "3"]
A:admin@node-2# info
interface "ipsec-priv" {
tunnel true
static-tunnel-redundant-nexthop 10.7.7.1
sap tunnel-1.private:100 {
}
}
Shunting in private service (classic CLI)
A:node-2>config>service>vprn$ info
----------------------------------------------
interface "ipsec-priv" tunnel create
sap tunnel-1.private:100 create
exit
static-tunnel-redundant-next-hop 10.7.7.1
exit
Configuring MCS encryption
The following examples show the configuration for MCS encryption.
Keychain example 1 (MD-CLI)
[ex:/configure system security keychains keychain "mcs"]
A:admin@node-2# info
bidirectional {
entry 2 {
authentication-key "KrbVPnF6Dg13PM/biw6ErIQyX4uD hash2"
algorithm aes-128-gcm-16
begin-time 2023-03-22T18:50:00.0+00:00
}
}
Keychain example 1 (classic CLI)
A:node-2>config>redundancy>multi-chassis>peer>sync>transport-encryption#
----------------------------------------------
application "ipsec" keychain ‟mcs”
exit
----------------------------------------------
A:node-2>config>system>security# info
----------------------------------------------
keychain "mcs"
direction
bi
entry 2 key "KrbVPnF6Dg13PM/biw6ErIQyX4uD" hash2 algorithm aes-128-gcm-16
begin-time 2023/03/22 18:50:00 UTC
exit
exit
exit
no shutdown
exit
Keychain example 2 (MD-CLI)
[ex:/configure system security]
A:admin@node-2# info
per-peer-queuing true
keychains {
keychain "mcs" {
bidirectional {
entry 2 {
authentication-key "KrbVPnF6Dg13PM/biw6ErIQyX4uD hash2"
algorithm aes-128-gcm-16
begin-time 2023-03-22T18:50:00.0+00:00
}
entry 3 {
authentication-key "/Ub6BWHC4DsEprLWutGaTcJz1zDPhw== hash2"
algorithm aes-128-gcm-16
begin-time 2023-03-22T21:30:00.0+00:00
}
entry 255 {
begin-time 2023-03-22T18:33:23.0+00:00
tolerance infinite
}
}
Keychain example 2 (classic CLI)
A:node-2>config>redundancy>multi-chassis>peer>sync>transport-encryption#
----------------------------------------------
application "ipsec" keychain ‟mcs”
exit
*A:node-2>config>system>security# info
----------------------------------------------
per-peer-queuing
keychain "mcs"
direction
bi
entry 2 key "KrbVPnF6Dg13PM/biw6ErIQyX4uD" hash2 algorithm aes-128-gcm-16
begin-time 2023/03/22 18:50:00 UTC
exit
entry 3 key "/Ub6BWHC4DsEprLWutGaTcJz1zDPhw==" hash2 algorithm aes-128-gcm-16
begin-time 2023/03/22 21:30:00 UTC
exit
entry null-key
begin-time 2023/03/22 18:33:23 UTC
tolerance forever
exit
exit
exit
no shutdown
exit
Configuring and using CMPv2
CMPv2 server information is configured using the commands in the following context.
configure system security pki ca-profile cmpv2
The following command options are configured in this context:
-
url
This command option specifies the HTTP URL of the CMPv2 server. The service specifies the routing instance that the system used to access the CMPv2 server (if omitted, then system uses the base routing instance).
-
service name or service ID
This command option is only needed for in-band connections to the server via VPRN services. IES services are not referenced by the service ID as they use the base routing instance.
-
response-signing-cert
This command option specifies an imported certificate used to verify the CMP response message if it is protected by signature. If this command is not configured, the CA certificate is used.
-
key-list
This command option specifies a list of pre-shared keys used for CMPv2 initial registration message protection.
If there is no key list defined in the CMPv2 configuration, the system defaults to the CMPv2 transaction input for the command line for authenticating a message without a sender ID. Also, if there is no sender ID in the response message, and there is a key list defined, the system chooses the lexicographical first entry only, and if that fails, it outputs a fail result for the transaction.
- MD-CLI
admin system security pki cmpv2
- classic
CLI
admin certificate cmpv2
The system also supports optional commands (such as, always-set-sender-ir) to support inter-op with CMPv2 servers.
The following example displays CMPv2 configuration.
MD-CLI
[ex:/configure system security pki ca-profile "profile" cmpv2]
A:admin@node-2# info
response-signing-cert "filename"
url {
url-string "http://cmp.example.com/request"
service-name "foo"
}
key-list {
key "1" {
password "RGwT0+xs+Zb9708mSFdzMCxTCu8ykxuSpA2mpHzFwzU= hash2"
}
}
classic CLI
A:node-2>config>system>security>pki>ca-profile>cmpv2$ info
----------------------------------------------
url "http://cmp.example.com/request" service-name "foo"
key-list
key "RGwT0+xs+Zb9708mSFdzMCxTCu8ykxuSpA2mpHzFwzU=" hash2 reference "1"
exit
response-signing-cert "filename"
----------------------------------------------
Configuring OCSP
OCSP server information is configured using the following command.
configure system security pki ca-profile ocsp
The responder-url command option specifies the HTTP URL of the OCSP responder. The service ID or service name command option specifies the routing instance that system used to access the OCSP responder.
For an IPsec tunnel or IPsec gateway, the user can configure a primary method, a secondary method and a default result using the following commands:
- MD-CLI
configure ipsec ipsec-transport-mode-profile key-exchange dynamic cert status-verify configure router interface ipsec ipsec-tunnel key-exchange dynamic cert status-verify configure service ies interface ipsec ipsec-tunnel key-exchange dynamic cert status-verify configure service vprn interface ipsec ipsec-tunnel key-exchange dynamic cert status-verify configure service vprn interface sap ipsec-tunnel key-exchange dynamic cert status-verify
- classic
CLI
configure service vprn interface sap ipsec-gw cert status-verify configure service ies interface sap ipsec-gw cert status-verify configure service vprn interface ipsec ipsec-tunnel dynamic-keying cert status-verify configure service vprn interface sap ipsec-tunnel dynamic-keying cert status-verify configure service ies interface ipsec ipsec-tunnel dynamic-keying cert status-verify
The following example, shows OCSP configured as the primary method and CRL as the secondary method.
MD-CLI
[ex:/configure service ies "2" interface "ipsec-pub" sap tunnel-1.public:100 ipsec-gateway "foo"]
A:admin@node-2# info
cert {
status-verify {
primary ocsp
secondary crl
}
}
classic CLI
A:node-2>config>service>ies>if>sap>ipsec-gw# info
----------------------------------------------
shutdown
cert
status-verify
primary ocsp secondary crl
exit
exit
----------------------------------------------
Configuring IKEv2 remote-access tunnel
The following are configuration tasks for an IKEv2 remote-access tunnel:
-
Create an IKE policy with one of the authentication methods that enabled the remote-access tunnel.
-
Configure a tunnel template or IPsec transform. This is the same as configuring a dynamic LAN-to-LAN tunnel.
-
Create a RADIUS authentication policy and optionally, a RADIUS accounting policy (a RADIUS server policy and a RADIUS server must be preconfigured).
-
Configure a private VPRN service and private tunnel interface with an address on the interface. The internal address assigned to the client must come from the subnet on the private interface.
-
Configure a public IES or VPRN service and an IPsec gateway under the public tunnel SAP.
-
Configure the RADIUS authentication policy and RADIUS accounting policy (optional) under the IPsec gateway.
-
Configure a certificate if any certificate-related authentication method is used.
The following example shows an IKEv2 configuration using cert-radius.
MD-CLI
[ex:/configure system security pki]
A:admin@node-2# info
ca-profile "NOKIA-ROOT" {
admin-state enable
cert-file "NOKIA-ROOT.cert"
crl-file "NOKIA-ROOT.crl"
}
[ex:/configure aaa]
A:admin@node-2# info
radius {
server-policy "femto-aaa" {
servers {
router-instance "management"
server 1 {
server-name "svr-1"
}
}
}
}
[ex:/configure router "Base"]
A:admin@node-2# info
radius {
server "svr-1" {
address 10.10.1.2
secret "LCa0a2j/xo/5m0U8HTBBNJYdag== hash2"
}
}
[ex:/configure ipsec]
A:admin@node-2# info
cert-profile "c1" {
admin-state enable
entry 1 {
cert "SeGW2.cert"
key "SeGW2.key"
}
}
ike-policy 1 {
ike-transform [1]
ike-version-2 {
auth-method cert-radius
}
}
ike-transform 1 {
}
ipsec-transform 1 {
}
tunnel-template 1 {
ipsec-transform [1]
}
trust-anchor-profile "tap-1" {
trust-anchor "NOKIA-ROOT" { }
}
radius {
accounting-policy "femto-acct" {
radius-server-policy "femto-aaa"
include-radius-attribute {
calling-station-id true
framed-ip-addr true
}
}
authentication-policy "femto-auth" {
radius-server-policy "femto-aaa"
password "CQsjXp648Zfy3ZJ5NyIsV7gcSkI= hash2"
include-radius-attribute {
called-station-id true
calling-station-id true
}
}
}
[ex:/configure service ies "2"]
A:admin@node-2# info
admin-state enable
customer "1"
interface "pub" {
sap tunnel-1.public:100 {
ipsec-gateway "rw" {
admin-state enable
default-tunnel-template 1
ike-policy 1
cert {
cert-profile "c1"
trust-anchor-profile "tap-1"
}
default-secure-service {
service-name "priv"
interface "priv"
}
radius {
accounting-policy "femto-acct"
authentication-policy "femto-auth"
}
}
}
ipv4 {
primary {
address 172.16.100.0
prefix-length 31
}
}
}
[ex:/configure service vprn "1"]
A:admin@node-2# info
admin-state enable
bgp-ipvpn {
mpls {
admin-state enable
route-distinguisher "400:11"
}
}
interface "l1" {
loopback true
ipv4 {
primary {
address 10.9.9.9
prefix-length 32
}
}
}
interface "priv" {
tunnel true
ipv4 {
addresses {
address 10.20.20.1 {
prefix-length 24
}
}
}
sap tunnel-1.private:200 {
}
}
classic CLI
A:node-2>config>system>security>pki# info
----------------------------------------------
ca-profile "NOKIA-ROOT" create
cert-file "NOKIA-ROOT.cert"
crl-file "NOKIA-ROOT.crl"
no shutdown
exit
----------------------------------------------
A:node-2>config>aaa# info
----------------------------------------------
radius-server-policy "femto-aaa" create
servers
router "management"
server 1 name ‟svr-1"
exit
exit
----------------------------------------------
A:node-2>config>router# info
----------------------------------------------
radius-server
server ‟svr-
1" address 10.10.10.1 secret "KR35xB3W4aUXtL8o3WzPD." hash2 create
exit
exit
----------------------------------------------
A:node-2>config>ipsec# info
----------------------------------------------
ike-policy 1 create
ike-version 2
auth-method cert-radius
ike-transform 1
exit
ipsec-transform 1 create
exit
ike-transform 1 create
exit
tunnel-template 1 create
transform 1
exit
cert-profile "c1" create
entry 1 create
cert SeGW2.cert
key SeGW2.key
exit
no shutdown
exit
trust-anchor-profile "tap-1" create
trust-anchor "NOKIA-ROOT"
exit
radius-authentication-policy "femto-auth" create
include-radius-attribute
calling-station-id
called-station-id
exit
password "DJzlyYKCefyhomnFcFSBuLZovSemMKde" hash2
radius-server-policy "femto-aaa"
exit
radius-accounting-policy "femto-acct" create
include-radius-attribute
calling-station-id
framed-ip-addr
exit
radius-server-policy "femto-aaa"
exit
----------------------------------------------
A:node-2>config>service>ies# info
----------------------------------------------
interface "pub" create
address 172.16.100.0/31
tos-marking-state untrusted
sap tunnel-1.public:100 create
ipsec-gw "rw"
cert
trust-anchor-profile "tap-1"
cert-profile "c1"
exit
default-secure-service 400 interface "priv"
default-tunnel-template 1
ike-policy 1
local-gateway-address 172.16.100.1
radius-accounting-policy "femto-acct"
radius-authentication-policy "femto-auth"
no shutdown
exit
exit
exit
no shutdown
----------------------------------------------
A:node-2>config>service>vprn# info
----------------------------------------------
interface "priv" tunnel create
address 10.20.20.1/24
sap tunnel-1.private:200 create
exit
exit
interface "l1" create
address 10.9.9.9/32
loopback
exit
bgp-ipvpn
mpls
route-distinguisher 400:11
no shutdown
exit
exit
no shutdown
----------------------------------------------
Configuring IKEv2 remote-access tunnel with local address assignment
The following are configuration tasks of IKEv2 remote-access tunnel:
-
Create an IKE policy with any authentication method.
-
Configure the tunnel template or IPsec transform. This is the same as configuring a dynamic LAN-to-LAN tunnel.
-
Configure a private VPRN service and a private tunnel interface with an address on the interface. The internal address assigned to the client must come from the subnet on the private interface.
-
Configure a local DHCPv4 or DHCPv6 server with address pool that from which the internal address to be assigned from.
-
Configure public IES or VPRN service and IPsec gateway under public tunnel SAP.
-
Configure the local address assignment under the IPsec gateway.
The following example shows an IKEv2 remote-access tunnel using cert-auth.
MD-CLI
[ex:/configure system security pki]
A:admin@node-2# info
ca-profile "smallcell-root" {
admin-state enable
cert-file "smallcell-root-ca.cert"
revocation-check crl-optional
}
[ex:/configure ipsec]
A:admin@node-2# info
cert-profile "segw-mlab" {
admin-state enable
entry 1 {
cert "SeGW-MLAB.cert"
key "SeGW-MLAB.key"
}
}
ike-policy 3 {
ike-transform [1]
ike-version-2 {
auth-method cert
}
nat-traversal {
}
}
ike-transform 1 {
}
ipsec-transform 1 {
}
tunnel-template 1 {
ipsec-transform [1]
}
trust-anchor-profile "sc-root" {
trust-anchor "smallcell-root" {
}
}
[ex:/configure service ies "2"]
A:admin@node-2# info
admin-state enable
customer "1"
interface "pub" {
sap tunnel-1.public:100 {
ipsec-gateway "rw" {
admin-state enable
default-tunnel-template 1
ike-policy 3
cert {
cert-profile "segw-mlab"
trust-anchor-profile "sc-root"
status-verify {
default-result good
}
}
default-secure-service {
service-name "priv"
interface "priv"
}
local {
gateway-address 172.16.100.1
id {
fqdn "segwmobilelab.nokia.com"
}
address-assignment {
admin-state enable
ipv6 {
router-instance "priv"
dhcp-server "d6"
pool "1"
}
}
}
}
}
ipv4 {
primary {
address 172.16.100.253
prefix-length 24
}
}
}
[ex:/configure service vprn "3"]
A:admin@node-2# info
admin-state enable
bgp-ipvpn {
mpls {
admin-state enable
route-distinguisher "400:1"
}
}
interface "priv" {
admin-state enable
tunnel true
sap tunnel-1.private:200 {
}
ipv6 {
address 2001:db8:beef::101 {
prefix-length 96
}
}
}
dhcp-server {
dhcpv6 "d6" {
admin-state enable
pool-selection {
use-pool-from-client {
}
}
pool "1" {
options {
option dns-server {
hex-string 0x20010db8beef00000000000000000808
}
}
prefix 2001:db8:beef::/96 {
failover-control-type access-driven
}
exclude-prefix 2001:db8:beef::101/128 { }
}
}
}
classic CLI
A:node-2>config>system>security>pki# info
----------------------------------------------
ca-profile "smallcell-root" create
cert-file "smallcell-root-ca.cert"
revocation-check crl-optional
no shutdown
exit
----------------------------------------------
A:node-2>config>ipsec# info
----------------------------------------------
ike-policy 3 create
ike-version 2
auth-method cert-auth
nat-traversal
ike-transform 1
exit
ipsec-transform 1 create
exit
ike-transform 1 create
exit
cert-profile "segw-mlab" create
entry 1 create
cert SeGW-MLAB.cert
key SeGW-MLAB.key
exit
no shutdown
exit
trust-anchor-profile "sc-root" create
trust-anchor "smallcell-root"
exit
tunnel-template 1 create
transform 1
exit
----------------------------------------------
A:node-2>config>service>ies# info
----------------------------------------------
interface "pub" create
address 172.16.100.253/24
tos-marking-state untrusted
sap tunnel-1.public:100 create
ipsec-gw "rw"
default-secure-service 400 interface "priv"
default-tunnel-template 1
ike-policy 3
local-address-assignment
ipv6
address-source router 400 dhcp-server "d6" pool "1"
exit
no shutdown
exit
local-gateway-address 172.16.100.1
cert
trust-anchor-profile "sc-root"
cert-profile "segw-mlab"
status-verify
default-result good
exit
exit
local-id type fqdn value segwmobilelab.nokia.com
no shutdown
exit
exit
exit
no shutdown
----------------------------------------------
A:node-2>config>service>vprn# info
----------------------------------------------
dhcp6
local-dhcp-server "d6" create
use-pool-from-client
pool "1" create
options
dns-server 2001:db8:::808:808
exit
exclude-prefix 2001:db8:beef::101/128
prefix 2001:db8::beef::/96 failover access-driven pd wan-host create
exit
exit
no shutdown
exit
exit
bgp-ipvpn
mpls
route-distinguisher 400:1
no shutdown
exit
exit
interface "priv" tunnel create
ipv6
address 2001:db8:beef::101/96
exit
sap tunnel-1.private:200 create
exit
exit
no shutdown
Configuring secured interfaces
The following example displays a configuration for a secured interface. In this example, a SI tunnel ‟t1” is configured under interface ‟toPeer-1” in Base routing instance, along with an exception filter 100 that allows OSPF packets bypass IPsec processing.
MD-CLI
[ex:/configure filter]
A:admin@node-2# info
ip-exception "100" {
entry 10 {
match {
protocol ospf-igp
}
}
}
*[ex:/configure router "Base"]
A:admin@node-2# info
interface "toPeer-1" {
ipsec {
tunnel-group 1
public-sap 300
ip-exception "100"
ipsec-tunnel "t1" {
private-sap 300
local-gateway-address-override 192.168.110.20
remote-gateway-address 172.16.21.1
key-exchange {
dynamic {
ike-policy 3
ipsec-transform [2]
pre-shared-key "mEg8brQLbDGkSMIqZt7TtTpKaT7xPCY= hash2"
}
}
security-policy {
id 1
}
}
}
ipv4 {
primary {
address 192.168.110.20
prefix-length 24
}
}
}
ipsec {
security-policy 1 {
entry 1 {
local-ip {
address 100.0.0.20/32
}
remote-ip {
address 200.1.1.254/32
}
}
}
}
classic CLI
config>filter# info
----------------------------------------------
ip-exception 100 create
entry 10 create
match protocol ospf-igp
exit
exit
exit
----------------------------------------------
config>router# info
----------------------------------------------
#--------------------------------------------------
echo "IPsec Configuration"
#--------------------------------------------------
ipsec
security-policy 1 create
entry 1 create
local-ip 100.0.0.20/32
remote-ip 200.1.1.254/32
exit
exit
exit
#--------------------------------------------------
echo "IP Configuration"
#--------------------------------------------------
interface "toPeer-1"
address 192.168.110.20/24
port 1/1/3
ipsec tunnel-group 1 public-sap 300
ip-exception 100
ipsec-tunnel "t1" private-sap 300 create
local-gateway-address 192.168.110.20
remote-gateway-address 172.16.21.1
security-policy 1
dynamic-keying
ike-policy 3
pre-shared-key "KrbVPnF6Dg13PM/biw6ErD9+g6HZ" hash2
transform 2
exit
Quantum-safe IPsec
A quantum computer is built on top of quantum mechanics. A key use case for quantum computers is the potential capability to break existing asymmetric cryptography algorithms, such as Diffie-Hellman (DH) exchange, RSA, ECDSA, and so on. For IPsec, this impacts the following areas:
- Key exchange
- PKI-based authentication
Standards for quantum-safe algorithms are in development, but in the interim, a phased approach is required in the migration to quantum-safe IPSec. Of the two impacted areas, key exchange is more urgent to address than PKI authentication, because it serves as the security foundation of IPsec protocols.
Secure IKEv2 key exchange via PPK
Traditionally, IKEv2 uses DH or Elliptic-curve DH (ECDH) for all its key derivations during IKE_SA_INIT or IKE_SA/CHILD_SA rekey exchanges.
SR OS supports the ability to mix a Post-quantum Preshared Key (PPK) into the IKEv2 key derivation process, along with traditional DH or ECDH exchanges, as defined in RFC 8784. This feature adds quantum resistance to the IKEv2 protocol until quantum-safe algorithms become available for use. The PPK is a user-provisioned, preshared key that is used to derive the following keys, on top of the key derivation process defined in RFC 7296:
-
SK_d - used to derive the CHILD_SA keys and rekey
-
SK_pi - used for authentication
-
SK_pr - used for authentication
If the PPK has enough entropy, the ESP traffic and IKE traffic after the first IKE_SA rekey are secured against quantum computers.
PPK is supported with all IKEv2 authentication methods.
IKEv2 exchange with PPK
Initiator Responder
------------------------------------------------------------------
HDR, SAi1, KEi, Ni, N(USE_PPK) --->
<--- HDR, SAr1, KEr, Nr, [CERTREQ,] N(USE_PPK)
HDR, SK {IDi, [CERT,] [CERTREQ,]
[IDr,] AUTH, SAi2,
TSi, TSr, N(PPK_IDENTITY, PPK_ID), [N(NO_PPK_AUTH)]} --->
<-- HDR, SK {IDr, [CERT,]
AUTH, SAr2,
TSi, TSr, N(PPK_IDENTITY)}
Both peers signal support for PPK by including the USE_PPK notification in the IKE_SA_INIT exchange. Multiple PPKs can be provisioned, and each PPK is assigned a unique ID. The initiator must also include the ID of the selected PPK in the PPK_IDENTITY notification of IKE_AUTH request message and, optionally, include a NO_PPK_AUTH if using PPK is optional. The responder handles the IKE_AUTH request message in accordance with RFC 8784. The following table describes this handling.
Received USE_PPK | Received NO_PPK_AUTH | Configured with PPK | PPK is Mandatory | Action |
---|---|---|---|---|
No | – | No | – | Standard IKEv2 protocol |
No | – | Yes | No | Standard IKEv2 protocol |
No | – | Yes | Yes | Abort negotiation |
Yes | No | No | – | Abort negotiation |
Yes | Yes | No | Yes | Abort negotiation |
Yes | Yes | No | No | Standard IKEv2 protocol |
Yes | – | Yes | – | Use PPK |
Configuring PPK
Perform the following steps to configure PPK.
-
Use commands in the following context to configure a PPK list. The list can contain
multiple PPKs, each with a unique ID and value.
configure ipsec ppk-list
MD-CLI[gl:/configure ipsec] A:admin@node-2# ppk-list t1 ppk ppk-1 value hex 0x0123456789 [gl:/configure ipsec] A:admin@Dut-AD# ppk-list t1 ppk ppk-2 value ascii abcd1234++
[gl:/configure ipsec] A:admin@node-2# info ppk-list "t1" { ppk "ppk-1" { value { hex "2ySr4tCiD6yVeFnrdVs9v2ME1oRx hash2" } } ppk "ppk-2" { value { ascii "fHNsiyqqP9VW+Ovb+jEP1PN1zXyH/8ajq64= hash2" } } }
classic CLIA:node-2>config>ipsec# ppk-list t1 create ppk-id ppk-1 format hex value 0x123456789 A:node-2>config>ipsec# ppk-list t1 create ppk-id ppk-1 format ascii value abcd1234++
A:node-2>config>ipsec# info ---------------------------------------------- ppk-list "t1" create ppk-id "ppk-1" format hex value "2ySr4tCiD6yVeFnrdVs9vy4MTT0N" hash2 ppk-id "ppk-2" format ascii value "fHNsiyqqP9VW+Ovb+jEP1MD9JO9h8kbJMtQ=" hash2 exit
-
For the IPsec gateway, use the following command to reference the PPK list in the
tunnel template.
configure ipsec tunnel-template ppk-list
MD-CLI(gl:/configure ipsec tunnel-template 1] A:admin@node-2# info ppk-list "t1"
classic CLIA:node2>config>ipsec>tnl-temp# info ---------------------------------------------- ppk-list "t1"
-
For the IPsec tunnel, use commands in the following contexts to reference a specific
PPK in the PPK list.
- MD-CLI
configure router interface ipsec ipsec-tunnel key-exchange dynamic ppk configure service ies interface ipsec-tunnel key-exchange dynamic ppk configure service vprn interface sap ipsec-tunnel key-exchange dynamic ppk configure service vprn interface ipsec-tunnel key-exchange dynamic ppk
- classic
CLI
configure router interface ipsec ipsec-tunnel dynamic-keying ppk configure service ies interface ipsec-tunnel dynamic-keying ppk configure service vprn interface sap ipsec-tunnel dynamic-keying ppk configure service vprn interface ipsec-tunnel dynamic-keying ppk
MD-CLI[gl:/configure service vprn "400" interface "priv" sap tunnel-1.private:100 ipsec-tunnel "t1" key-exchange dynamic] A:admin@node-2# ppk list t1 id ppk-id 1
[gl:/configure service vprn "400" interface "priv" sap tunnel-1.private:100 ipsec-tunnel "t1" key-exchange dynamic] A:admin@node-2# info ppk { list "t1" id "ppk-1" }
classic CLIA:node-02>config>service>vprn>if>sap>ipsec-tun>dyn$ ppk list "t1" id "ppk-id1"
A:node-02>config>service>vprn>if>sap>ipsec-tun>dyn$ info ---------------------------------------------- ppk list "t1" id "ppk-1"
- MD-CLI
-
Use the following command to configure the mandatory use of PPK
under the IKE policy.
- MD-CLI
configure ipsec ike-policy ike-version-2 ppk-required
- classic
CLI
configure ipsec ike-policy ppk-required
MD-CLI(gl)[/configure ipsec ike-policy 1 ike-version-2] A:admin@node-2# info ppk-required true
classic CLIA:node-2>config>ipsec>ike-policy# info ---------------------------------------------- ike-version 2 ppk-required
- MD-CLI