Configuring Internet Key Exchange Version 2 and FlexVPN Site-to-Site
Last Updated: September 26, 2012
This module contains information about and instructions for configuring basic and advanced Internet Key Exchange Version 2 (IKEv2) and FlexVPN site-to-site. The tasks and configuration examples for IKEv2 in this module are divided as follows:
Basic IKEv2--Provides information about basic IKEv2 commands, IKEv2 smart defaults, basic IKEv2 profile, and IKEv2 key ring.
Advanced IKEv2--Provides information about global IKEv2 commands and how to override IKEv2 smart defaults.
Note
Security threats, as well as the cryptographic technologies to help protect against them, are constantly changing. For more information about the latest Cisco cryptographic recommendations, see the
Next Generation Encryption (NGE) white paper.
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see
Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Configuring Internet Key Exchange Version 2
You should be familiar with the concepts and tasks described in the "Configuring Security for VPNs with IPsec" module.
Restrictions for Configuring Internet Key Exchange Version 2
You cannot configure an option that is not supported on a specific platform. For example, in a security protocol, the capability of the hardware-crypto engine is important, and you cannot specify the Triple Data Encryption Standard (3DES) or the Advanced Encryption Standard (AES) type of encryption transform in a nonexportable image, or specify an encryption algorithm that a crypto engine does not support.
Cisco implements the IP Security (IPsec) Protocol standard for use in Internet Key Exchange Version 2 (IKEv2).
Note
Cisco no longer recommends using DES or MD5 (including HMAC variant); instead, you should use AES and SHA-256. For more information about the latest Cisco cryptographic recommendations, see the
Next Generation Encryption (NGE) white paper.
The component technologies implemented in IKEv2 are as follows:
For more information about supported standards and component technologies, see the "Supported Standards for Use with IKE" section in the "Configuring Internet Key Exchange for IPsec VPNs" module in the
Internet Key Exchange for IPsec VPNs Configuration Guide.
Benefits of IKEv2
Dead Peer Detection and Network Address Translation-Traversal
Internet Key Exchange Version 2 (IKEv2) provides built-in support for Dead Peer Detection (DPD) and Network Address Translation-Traversal (NAT-T).
Certificate URLs
Certificates can be referenced through a URL and hash, instead of being sent within IKEv2 packets, to avoid fragmentation.
Denial of Service Attack Resilience
IKEv2 does not process a request until it determines the requester, which addresses to some extent the Denial of Service (DoS) problems in IKEv1, which can be spoofed into performing substantial cryptographic (expensive) processing from false locations.
EAP Support
IKEv2 allows the use of Extensible Authentication Protocol (EAP) for authentication.
Multiple Crypto Engines
If your network has both IPv4 and IPv6 traffic and you have multiple crypto engines, choose one of the following configuration options:
One engine handles IPv4 traffic and the other engine handles IPv6 traffic.
One engine handles both IPv4 and IPv6 traffic.
Reliability and State Management (Windowing)
IKEv2 uses sequence numbers and acknowledgments to provide reliability, and mandates some error-processing logistics and shared state management.
An Internet Key Exchange Version 2 (IKEv2) proposal is a collection of transforms used in the negotiation of Internet Key Exchange (IKE) security associations (SAs) as part of the IKE_SA_INIT exchange. The transform types used in the negotiation are as follows:
Encryption algorithm
Integrity algorithm
Pseudo-Random Function (PRF) algorithm
Diffie-Hellman (DH) group
See the "IKEv2 Smart Defaults" section for information about the default IKEv2 proposal. See the "Configuring Advanced IKEv2 CLI Constructs" section for information about how to override the default IKEv2 proposal and to define new proposals.
IKEv2 Policy
An IKEv2 policy contains proposals that are used to negotiate the encryption, integrity, PRF algorithms, and DH group in the IKE_SA_INIT exchange. It can have match statements, which are used as selection criteria to select a policy during negotiation.
See the "IKEv2 Smart Defaults" section for information about the default IKEv2 policy. See the "Configuring Advanced IKEv2 CLI Constructs" section for information about how to override the default IKEv2 policy and to define new policies.
IKEv2 Profile
An IKEv2 profile is a repository of nonnegotiable parameters of the IKE SA, such as local or remote identities and authentication methods and services that are available to authenticated peers that match the profile. An IKEv2 profile must be attached to either a crypto map or an IPSec profile on the initiator. An IKEv2 profile is not mandatory on the responder.
IKEv2 Key Ring
An IKEv2 key ring is a repository of symmetric and asymmetric preshared keys and is independent of the IKEv1 key ring. The IKEv2 key ring is associated with an IKEv2 profile and hence supports a set of peers that match the IKEv2 profile. The IKEv2 key ring gets its VPN routing and forwarding (VRF) context from the associated IKEv2 profile.
IKEv2 Smart Defaults
The IKEv2 Smart Defaults feature minimizes the FlexVPN configuration by covering most of the use cases. IKEv2 smart defaults can be customized for specific use cases, though this is not recommended.
See the "Configuring Advanced IKEv2 CLI Constructs" section for information about how to modify the default IKEv2 constructs.
The following rules apply to the IKEv2 Smart Defaults feature:
A default configuration is displayed in the corresponding
show command with
default as a keyword and with no argument. For example, the
show crypto ikev2 proposal default command displays the default IKEv2 proposal and the
show crypto ikev2 proposal command displays the default IKEv2 proposal, along with any user-configured proposals.
A default configuration is displayed in the
show running-config all command; it is not displayed in the
show running-config command.
You can modify the default configuration, which is displayed in the
show running-config all command.
A default configuration can be disabled using the
no form of the command; for example,
no crypto ikev2 proposal default. A disabled default configuration is not used in negotiation but the configuration is displayed in the
show running-config command. A disabled default configuration loses any user modification and restores system-configured values.
A default configuration can be reenabled using the default form of the command, which restores system-configured values; for example,
default crypto ikev2 proposal.
The default mode for the default transform set is transport; the default mode for all other transform sets is tunnel.
Note
Cisco no longer recommends using MD5 (including HMAC variant) and Diffie-Hellman (DH) groups 1, 2 and 5; instead, you should use SHA-256 and DH Groups 14 or higher. For more information about the latest Cisco cryptographic recommendations, see the
Next Generation Encryption (NGE) white paper.
The following table lists the commands that are enabled with the IKEv2 Smart Defaults feature, along with the default values.
Table 1
IKEv2 Command Defaults
Command Name
Default Values
crypto ikev2 authorization policy
Device# show crypto ikev2 authorization policy default
IKEv2 Authorization policy: default
route set interface
route accept any tag: 1 distance: 2
Device# show crypto ikev2 policy default
IKEv2 policy: default
Match fvrf: any
Match address local: any
Proposal: default
crypto ipsec profile
Device# show crypto ipsec profile default
IPSEC profile default
Security association lifetime: 4608000 kilobytes/3600 seconds
Responder-Only (Y/N): N
PFS (Y/N): N
Transform sets={
default: { esp-aes esp-sha-hmac },
}
crypto ipsec transform-set
Device# show crypto ipsec transform-set default
Transform set default: { esp-aes esp-sha-hmac }
will negotiate = { Tunnel, },
Note
Before you can use the default IPsec profile, explicitly specify the
crypto ipsec profile command on a tunnel interface using the
tunnel protection ipsec profile default command.
IKEv2 Suite-B Support
Suite-B is a set of cryptographic algorithms promulgated by the National Security Agency as part of its Cryptographic Modernization Program. Suite-B for Internet Key Exchange (IKE) and IPsec is defined in RFC 4869. The Suite-B components are as follows:
Advanced Encryption Standard (AES) 128- and 256-bit keys configured in the IKEv2 proposal. For data traffic, AES should be used in Galois Counter Mode (GCM) that is configured in the IPsec transform set.
Elliptic Curve Digital Signature Algorithm (ECDSA) configured in the IKEv2 profile.
Secure Hashing Algorithm 2 (SHA-256 and SHA-384) configured in the IKEv2 proposal and IPsec transform set.
Suite-B requirements comprise four user-interface suites of cryptographic algorithms for use with IKE and IPsec. Each suite consists of an encryption algorithm, a digital-signature algorithm, a key-agreement algorithm, and a hash- or message-digest algorithm. See the "Configuring Security for VPNs with IPsec" feature module for detailed information about Cisco Suite-B support.
Configuring Basic Internet Key Exchange Version 2 CLI Constructs
To enable IKEv2 on a crypto interface, attach an Internet Key Exchange Version 2 (IKEv2) profile to the crypto map or IPsec profile applied to the interface. This step is optional on the IKEv2 responder.
Note
The difference between IKEv1 and IKEv2 is that you need not enable IKEv1 on individual interfaces because IKEv1 is enabled globally on all interfaces on a device.
Perform the following tasks to manually configure basic IKEv2 constructs:
Perform this task to configure the IKEv2 key ring if the local or remote authentication method is a preshared key.
IKEv2 key ring keys must be configured in the peer configuration submode that defines a peer subblock. An IKEv2 key ring can have multiple peer subblocks. A peer subblock contains a single symmetric or asymmetric key pair for a peer or peer group identified by any combination of the hostname, identity, and IP address.
IKEv2 key rings are independent of IKEv1 key rings. The key differences are as follows:
IKEv2 key rings support symmetric and asymmetric preshared keys.
IKEv2 key rings do not support Rivest, Shamir, and Adleman (RSA) public keys.
IKEv2 key rings are specified in the IKEv2 profile and are not looked up, unlike IKEv1, where keys are looked up on receipt of MM1 to negotiate the preshared key authentication method. The authentication method is not negotiated in IKEv2.
IKEv2 key rings are not associated with VPN routing and forwarding (VRF) during configuration. The VRF of an IKEv2 key ring is the VRF of the IKEv2 profile that refers to the key ring.
A single key ring can be specified in an IKEv2 profile, unlike an IKEv1 profile, which can specify multiple key rings.
A single key ring can be specified in more than one IKEv2 profile, if the same keys are shared across peers matching different profiles.
An IKEv2 key ring is structured as one or more peer subblocks.
On an IKEv2 initiator, the IKEv2 key ring key lookup is performed using the peer's hostname or the address, in that order. On an IKEv2 responder, the key lookup is performed using the peer's IKEv2 identity or the address, in that order.
Note
You cannot configure the same identity in more than one peer.
After configuring the IKEv2 key ring, configure the IKEv2 profile. For more information, see the "Configuring IKEv2 Profile (Basic)" section.
Configuring an IKEv2 Profile (Basic)
Perform this task to configure the mandatory commands for an IKEv2 profile.
An IKEv2 profile is a repository of nonnegotiable parameters of the IKE security association (SA) (such as local or remote identities and authentication methods) and services available to authenticated peers that match the profile. An IKEv2 profile must be configured and associated with either a crypto map or an IPsec profile on the IKEv2 initiator. Use the
set ikev2-profile profile-name
command to associate a profile with a crypto map or an IPsec profile. To disassociate the profile, use the
no form of the command.
The following rules apply to match statements:
An IKEv2 profile must contain a match identity or a match certificate statement; otherwise, the profile is considered incomplete and is not used. An IKEv2 profile can have more than one match identity or match certificate statements.
An IKEv2 profile must have a single match Front Door VPN routing and forwarding (FVRF) statement.
When a profile is selected, multiple match statements of the same type are logically ORed, and multiple match statements of different types are logically ANDed.
The match identity and match certificate statements are considered to be the same type of statements and are ORed.
Configuration of overlapping profiles is considered a misconfiguration. In the case of multiple profile matches, no profile is selected.
Use the
show crypto ikev2 profile profile-name
command to display the IKEv2 profile.
Device(config-ikev2-profile)# identity local email abc@example.com
(Optional) Specifies the local IKEv2 identity type.
Note
If the local authentication method is a preshared key, the default local identity is the IP address. If the local authentication method is a Rivest, Shamir, and Adleman (RSA) signature, the default local identity is a Distinguished Name.
Step 9
initial-contact [force]
Example:
Device(config-ikev2-profile)# initial-contact force
Enforces initial contact processing if the initial contact notification is not received in the IKE_AUTH exchange.
Step 10
ivrf name
Example:
Device(config-ikev2-profile)# ivrf vrf1
(Optional) Specifies a user-defined VPN routing and forwarding (VRF) or global VRF if the IKEv2 profile is attached to a crypto map.
If the IKEv2 profile is used for tunnel protection, the Inside VRF (IVRF) for the tunnel interface should be configured on the tunnel interface.
Note
IVRF specifies the VRF for cleartext packets. The default value for IVRF is FVRF.
Specifies Public Key Infrastructure (PKI) trustpoints for use with the RSA signature authentication method.
Note
If the
sign or
verify keyword is not specified, the trustpoint is used for signing and verification.
Note
In contrast to IKEv1, a trustpoint must be configured in an IKEv2 profile for certificate-based authentication to succeed. There is no fallback for globally configured trustpoints if this command is not present in the configuration. The trustpoint configuration applies to the IKEv2 initiator and responder.
(Optional) Specifies the virtual template for cloning a virtual access interface (VAI).
Note
For the IPsec Dynamic Virtual Tunnel Interface (DVTI), a virtual template must be specified in an IKEv2 profile, without which an IKEv2 session is not initiated.
Step 18
end
Example:
Device(config-ikev2-profile)# end
Exits IKEv2 profile configuration mode and returns to privileged EXEC mode.
Configuring Advanced Internet Key Exchange Version 2 CLI Constructs
This section describes the global IKEv2 CLI constructs and how to override the IKEv2 default CLI constructs. IKEv2 smart defaults support most use cases and hence, we recommend that you override the defaults only if they are required for specific use cases not covered by the defaults.
Perform the following tasks to configure advanced IKEv2 CLI constructs:
Connection admission control is disabled by default.
Step 9
crypto ikev2 nat keepaliveinterval
Example:
Device(config)# crypto ikev2 nat keepalive 500
Enables the Network Address Translation (NAT) keepalive that prevents the deletion of NAT entries in the absence of any traffic when there is NAT between Internet Key Exchange (IKE) peers.
NAT keepalive is disabled by default.
Step 10
crypto ikev2 windowsize
Example:
Device(config)# crypto ikev2 window 15
Allows multiple IKEv2 request-response pairs in transit.
The default window size is 5.
Step 11
crypto logging ikev2
Example:
Device(config)# crypto logging ikev2
Enables IKEv2 syslog messages.
IKEv2 syslog messages are disabled by default.
Step 12
end
Example:
Device(config)# end
Exits global configuration mode and returns to privileged EXEC mode.
Configuring IKEv2 Fragmentation
Perform this task to enable automatic fragmentation of large IKEv2 packets.
SUMMARY STEPS
1.enable
2.configure terminal
3.crypto ikev2 fragmentation [mtumtu-size]
4.end
DETAILED STEPS
Command or Action
Purpose
Step 1
enable
Example:
Device> enable
Enables privileged EXEC mode.
Enter your password if prompted.
Step 2
configure terminal
Example:
Device# configure terminal
Enters global configuration mode.
Step 3
crypto ikev2 fragmentation [mtumtu-size]
Example:
Device(config)# crypto ikev2 fragmentation mtu 100
Configures IKEv2 fragmentation.
Note
The MTU size refers to the IP or UDP encapsulated IKEv2 packets.
Step 4
end
Example:
Device(config)# end
Exits global configuration mode and returns to privileged EXEC mode.
Configuring IKEv2 Proposal
Refer to the "IKEv2 Smart Defaults" section for information on the default IKEv2 proposal.
Perform this task to override the default IKEv2 proposal or to manually configure the proposals if you do not want to use the default proposal.
An IKEv2 proposal is a set of transforms used in the negotiation of IKEv2 SA as part of the IKE_SA_INIT exchange. An IKEv2 proposal is regarded as complete only when it has at least an encryption algorithm, an integrity algorithm, and a Diffie-Hellman (DH) group configured. If no proposal is configured and attached to an IKEv2 policy, the default proposal in the default IKEv2 policy is used in negotiation.
Note
Security threats, as well as the cryptographic technologies to help protect against them, are constantly changing. For more information about the latest Cisco cryptographic recommendations, see the
Next Generation Encryption (NGE) white paper.
Although the IKEv2 proposal is similar to the
crypto isakmp policy command, the IKEv2 proposal differs as follows:
An IKEv2 proposal allows configuring one or more transforms for each transform type.
An IKEv2 proposal does not have any associated priority.
Specifies one or more transforms of the encryption type, which are as follows:
3des (No longer recommended)
aes-cbc-128
aes-cbc-192
aes-cbc-256
Step 5
integrity {md5} {sha1} {sha256} {sha384} {sha512}
Example:
Device(config-ikev2-proposal)# integrity sha1
Specifies one or more transforms of the integrity algorithm type, which are as follows:
The
md5 keyword specifies MD5 (HMAC variant) as the hash algorithm. (No longer recommended)
The
sha1 keyword specifies SHA-1 (HMAC variant) as the hash algorithm.
The
sha256 keyword specifies SHA-2 family 256-bit (HMAC variant) as the hash algorithm.
The
sha384 keyword specifies SHA-2 family 384-bit (HMAC variant) as the hash algorithm.
The
sha512 keyword specifies SHA-2 family 512-bit (HMAC variant) as the hash algorithm.
Step 6
group {1} {14} {15} {16} {19} {2} {20} {24} {5}
Example:
Device(config-ikev2-proposal)# group 14
Specifies the Diffie-Hellman (DH) group identifier.
The default DH group identifiers are group 2 and 5 in the IKEv2 proposal.
1--768-bit DH (No longer recommended).
2--1024-bit DH (No longer recommended).
5--1536-bit DH (No longer recommended).
14--Specifies the 2048-bit DH group.
15--Specifies the 3072-bit DH group.
16--Specifies the 4096-bit DH group.
19--Specifies the 256-bit elliptic curve DH (ECDH) group.
20--Specifies the 384-bit ECDH group.
24--Specifies the 2048-bit DH group.
The group chosen must be strong enough (have enough bits) to protect the IPsec keys during negotiation. A generally accepted guideline recommends the use of a 2048-bit group after 2013 (until 2030). Either group 14 or group 24 can be selected to meet this guideline. Even if a longer-lived security method is needed, the use of Elliptic Curve Cryptography is recommended, but group 15 and group 16 can also be considered.
Step 7
end
Example:
Device(config-ikev2-proposal)# end
Exits IKEv2 proposal configuration mode and returns to privileged EXEC mode.
After you create the IKEv2 proposal, attach it to a policy so that the proposal is picked for negotiation. For information about completing this task, see the "Configuring IKEv2 Policy" section.
Configuring IKEv2 Policies
See the "IKEv2 Smart Defaults" section for information about the default IKEv2 policy.
Perform this task to override the default IKEv2 policy or to manually configure the policies if you do not want to use the default policy.
An IKEv2 policy must contain at least one proposal to be considered as complete and can have match statements, which are used as selection criteria to select a policy for negotiation. During the initial exchange, the local address (IPv4 or IPv6) and the Front Door VRF (FVRF) of the negotiating SA are matched with the policy and the proposal is selected.
The following rules apply to the match statements:
An IKEv2 policy without any match statements will match all peers in the global FVRF.
An IKEv2 policy can have only one match FVRF statement.
An IKEv2 policy can have one or more match address local statements.
When a policy is selected, multiple match statements of the same type are logically ORed and match statements of different types are logically ANDed.
There is no precedence between match statements of different types.
Configuration of overlapping policies is considered a misconfiguration. In the case of multiple, possible policy matches, the first policy is selected.
SUMMARY STEPS
1.enable
2.configureterminal
3.cryptoikev2policyname
4.proposalname
5.matchfvrf{fvrf-name |
any}
6.matchaddresslocal {ipv4-address|ipv6-address}
7.end
8.showcryptoikev2policy[policy-name |
default]
DETAILED STEPS
Command or Action
Purpose
Step 1
enable
Example:
Device> enable
Enables privileged EXEC mode.
Enter your password if prompted.
Step 2
configureterminal
Example:
Device# configure terminal
Enters global configuration mode.
Step 3
cryptoikev2policyname
Example:
Device(config)# crypto ikev2 policy policy1
Overrides the default IKEv2 policy, defines an IKEv2 policy name, and enters IKEv2 policy configuration mode.
Step 4
proposalname
Example:
Device(config-ikev2-policy)# proposal proposal1
Specifies the proposals that must be used with the policy.
The proposals are prioritized in the order of listing.
Note
You must specify at least one proposal. You can specify additional proposals with each proposal in a separate statement.
Step 5
matchfvrf{fvrf-name |
any}
Example:
Device(config-ikev2-policy)# match fvrf any
(Optional) Matches the policy based on a user-configured FVRF or any FVRF.
The default is global FVRF.
Note
The
match fvrf any command must be explicitly configured in order to match any VRF. The FVRF specifies the VRF in which the IKEv2 packets are negotiated.
Step 6
matchaddresslocal {ipv4-address|ipv6-address}
Example:
Device(config-ikev2-policy)# match address local 10.0.0.1
(Optional) Matches the policy based on the local IPv4 or IPv6 address.
The default matches all the addresses in the configured FVRF.
Step 7
end
Example:
Device(config-ikev2-policy)# end
Exits IKEv2 policy configuration mode and returns to privileged EXEC mode.
Step 8
showcryptoikev2policy[policy-name |
default]
Example:
Device# show crypto ikev2 policy policy1
(Optional) Displays the IKEv2 policy.
Configuration Examples for Internet Key Exchange Version 2
Example: IKEv2 Keyring with Symmetric Preshared Keys Based on an IP Address
The following example shows how to configure an IKEv2 key ring with symmetric preshared keys based on an IP address. The following is the initiator's key ring:
Example: IKEv2 Key Ring with Asymmetric Preshared Keys Based on an IP Address
The following example shows how to configure an IKEv2 key ring with asymmetric preshared keys based on an IP address. The following is the initiator's key ring:
crypto ikev2 keyring keyring-1
peer peer1
description peer1 with asymmetric keys
address 209.165.200.225 255.255.255.224
pre-shared-key local key1
pre-shared-key remote key2
The following is the responder's key ring:
crypto ikev2 keyring keyring-1
peer peer2
description peer2 with asymmetric keys
address 209.165.200.228 255.255.255.224
pre-shared-key local key2
pre-shared-key remote key1
Example: IKEv2 Key Ring with Asymmetric Preshared Keys Based on a Hostname
The following example shows how to configure an IKEv2 key ring with asymmetric preshared keys based on the hostname. The following is the initiator's key ring:
crypto ikev2 keyring keyring-1
peer host1
description host1 in example domain
hostname host1.example.com
pre-shared-key local key1
pre-shared-key remote key2
The following is the responder's keyring:
crypto ikev2 keyring keyring-1
peer host2
description host2 in abc domain
hostname host2.example.com
pre-shared-key local key2
pre-shared-key remote key1
Example: IKEv2 Key Ring with Symmetric Preshared Keys Based on an Identity
The following example shows how to configure an IKEv2 key ring with symmetric preshared keys based on an identity:
crypto ikev2 keyring keyring-4
peer abc
description example domain
identity fqdn example.com
pre-shared-key abc-key-1
peer user1
description user1 in example domain
identity email user1@example.com
pre-shared-key abc-key-2
peer user1-remote
description user1 example remote users
identity key-id example
pre-shared-key example-key-3
Example: IKEv2 Key Ring with a Wildcard Key
The following example shows how to configure an IKEv2 key ring with a wildcard key:
In the example shown, the key lookup for peer 10.0.0.1 first matches the wildcard key example-key, then the prefix key example-key, and finally the host key host1-example-key. The best match host1-example-key is used.
In the example shown, the key lookup for peer 10.0.0.1 would first match the host key host1-abc-key. Because this is a specific match, no further lookup is performed.
The following profile supports peers that identify themselves using fully qualified domain name (FQDN) example.com and authenticate with the RSA signature using trustpoint-remote. The local node authenticates itself with a preshared key using keyring-1.
Example: Configuring FlexVPN Site-to-Site with Dynamic Routing Using Certificates and IKEv2 Smart Defaults
The following examples show a site-to-site connection between a branch device (initiator, using a static virtual tunnel interface [sVTI]) and a central device (responder, using a dynamic virtual tunnel interface [dVTI]) with dynamic routing over the tunnel. The example uses IKEv2 smart defaults, and the authentication is performed using certificates (RSA signatures).
Note
A RSA modulus size of 2048 is recommended.
The peers use the FQDN as their IKEv2 identity, and the IKEv2 profile on the responder matches the domain in the identity FQDN.
The configuration on the initiator (branch device) is as follows:
hostname branch
ip domain name cisco.com
!
crypto ikev2 profile branch-to-central
match identity remote fqdn central.cisco.com
identity local fqdn branch.cisco.com
authentication local rsa-sig
authentication remote rsa-sig
pki trustpoint CA
!
crypto ipsec profile svti
set ikev2-profile branch-to-central
!
interface Tunnel0
ip address 172.16.0.101 255.255.255.0
tunnel source Ethernet0/0
tunnel mode ipsec ipv4
tunnel destination 10.0.0.100
tunnel protection ipsec profile svti
!
interface Ethernet0/0
ip address 10.0.0.101 255.255.255.0
!
interface Ethernet1/0
ip address 192.168.101.1 255.255.255.0
!
router rip
version 2
passive-interface Ethernet1/0
network 172.16.0.0
network 192.168.101.0
no auto-summary
The configuration on the responder (central router) is as follows:
hostname central
ip domain name cisco.com
!
crypto ikev2 profile central-to-branch
match identity remote fqdn domain cisco.com
identity local fqdn central.cisco.com
authentication local rsa-sig
authentication remote rsa-sig
pki trustpoint CA
virtual-template 1
!
interface Loopback0
ip address 172.16.0.100 255.255.255.0
!
interface Ethernet0/0
ip address 10.0.0.100 255.255.255.0
!
interface Ethernet1/0
ip address 192.168.100.1 255.255.255.0
!
interface Virtual-Template1 type tunnel
ip unnumbered Loopback0
tunnel source Ethernet0/0
tunnel mode ipsec ipv4
tunnel protection ipsec profile default
!
router rip
version 2
passive-interface Ethernet1/0
network 172.16.0.0
network 192.168.100.0
no auto-summary
Configuration Examples for Advanced Internet Key Exchange Version 2 CLI Constructs
Cisco no longer recommends using 3DES, MD5 (including HMAC variant), and Diffie-Hellman(DH) groups 1, 2 and 5; instead, you should use AES, SHA-256 and DH Groups 14 or higher. For more information about the latest Cisco cryptographic recommendations, see the
Next Generation Encryption (NGE) white paper.
The IKEv2 proposal proposal-2 shown translates to the following prioritized list of transform combinations:
aes-cbc-128, sha1, 14
aes-cbc-192, sha1, 14
Example: IKEv2 Proposals on the Initiator and Responder
The following example shows how to configure IKEv2 proposals on the initiator and the responder. The proposal on the initiator is as follows:
In the proposals shown for the initiator and responder, the initiator and responder have conflicting preferences. In this case, the initiator is preferred over the responder.
Redirect Mechanism for the Internet Key Exchange Protocol Version 2 (IKEv2)
Technical Assistance
Description
Link
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Feature Information for Configuring Internet Key Exchange Version 2 (IKEv2) and FlexVPN Site-to-Site
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
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Table 2
Feature Information for Configuring Internet Key Exchange Version 2 (IKEv2) and FlexVPN Site-to-Site
Feature Name
Releases
Feature Information
IKEv2 Site to Site
15.1(1)T
15.2(4)S
IKEv2 is a component of IP Security (IPsec) and is used for performing mutual authentication and establishing and maintaining security associations (SAs).
The following commands were introduced or modified:
aaa accounting (IKEv2 profile), address (IKEv2 keyring), authentication (IKEv2 profile), crypto ikev2 keyring, crypto ikev2 policy, crypto ikev2 profile, crypto ikev2 proposal, description (IKEv2 keyring), dpd, hostname (IKEv2 keyring), identity (IKEv2 keyring), identity local, ivrf, keyring, lifetime (IKEv2 profile), match (IKEv2 profile), nat, peer, pki trustpoint, pre-shared-key (IKEv2 keyring), proposal, virtual-template (IKEv2 profile), clear crypto ikev2 sa, clear crypto ikev2 stat, clear crypto session, clear crypto ikev2 sa, debug crypto ikev2, show crypto ikev2 diagnose error, show crypto ikev2 policy, show crypto ikev2 profile, show crypto ikev2 proposal, show crypto ikev2 sa, show crypto ikev2 session, show crypto ikev2 stats, show crypto session, show crypto socket.
IPv6 support for IPSec and IKEv2
15.1(4)M
This feature allows IPv6 addresses to be added to IPSec and IKEv2 protocols.
The following commands were introduced or modified:
address (IKEv2 keyring), identity (IKEv2 keyring), identity local, match (IKEv2 policy), and match (IKEv2 profile), show crypto ikev2 session, show crypto ikev2 sa, show crypto ikev2 profile, show crypto ikev2 policy, debug crypto condition, clear crypto ikev2 sa.
Suite-B support in IOS SW crypto
15.1(2)T
Suite-B adds support for the SHA-2 family (HMAC variant) hash algorithm used to authenticate packet data and verify the integrity verification mechanisms for the IKEv2 proposal configuration. HMAC is a variant that provides an additional level of hashing.
Suite-B also allows the Elliptic Curve Digital Signature Algorithm (ECDSA) signature (ECDSA-sig), as defined in RFC 4754, to be the authentication method for IKEv2.
Suite-B requirements comprise of four user interface suites of cryptographic algorithms for use with IKE and IPSec that are described in RFC 4869. Each suite is consists of an encryption algorithm, a digital signature algorithm, a key agreement algorithm, and a hash or message digest algorithm. See the Configuring Security for VPNs with IPsec module for more information about Cisco IOS Suite-B support.
The following commands were introduced or modified:
authentication, group, identity (IKEv2 profile), integrity, match (IKEv2 profile).
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