Cisco IOS XE Security Configuration Guide: Secure Connectivity, Release 2

Certificate to ISAKMP Profile Mapping

The Certificate to ISAKMP Profile Mapping feature enables you to assign an Internet Security Association and Key Management Protocol (ISAKMP) profile to a peer on the basis of the contents of arbitrary fields in the certificate. In addition, this feature allows you to assign a group name to those peers that are assigned an ISAKMP profile.

Finding Feature Information

For the latest feature information and caveats, see 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 for Certificate to ISAKMP Profile Mapping" section.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS XE software image support. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp. An account on Cisco.com is not required.

Contents

•Prerequisites for Certificate to ISAKMP Profile Mapping

•Restrictions for Certificate to ISAKMP Profile Mapping

•Information About Certificate to ISAKMP Profile Mapping

•How to Configure Certificate to ISAKMP Profile Mapping

•Configuration Examples for Certificate to ISAKMP Profile Mapping

•Additional References

•Feature Information for Certificate to ISAKMP Profile Mapping

Prerequisites for Certificate to ISAKMP Profile Mapping

•You should be familiar with configuring certificate maps.

•You should be familiar with configuring ISAKMP profiles.

Restrictions for Certificate to ISAKMP Profile Mapping

•This feature will not be applicable if you use Rivest, Shamir, and Adelman- (RSA-) signature or RSA-encryption authentication without certificate exchange. ISAKMP peers must be configured to do RSA-signature or RSA-encryption authentication using certificates.

•When there are two or more ISAKMP profiles, each having a different trustpoint enrolled in the same certificate authority server, the responder selects the last global trustpoint. This is because trustpoints are selected in the reverse order in which they are defined globally. For the IPsec tunnel establishment to be successful for peers, the trustpoint selected by the initiator should match the trustpoint selected by the responder. All other IPsec tunnels will fail to establish connection if the trustpoints do not match.

Information About Certificate to ISAKMP Profile Mapping

•Certificate to ISAKMP Profile Mapping Overview

•How Certificate to ISAKMP Profile Mapping Works

•Assigning an ISAKMP Profile and Group Name to a Peer

Certificate to ISAKMP Profile Mapping Overview

Prior to Cisco IOS XE Release 2.1, the only way to map a peer to an ISAKMP profile was as follows. The ISAKMP identity field in the ISAKMP exchange was used for mapping a peer to an ISAKMP profile. When certificates were used for authentication, the ISAKMP identity payload contained the subject name from the certificate. If a certificate authority (CA) did not provide the required group value in the first Organizational Unit (OU) field of a certificate, an ISAKMP profile could not be assigned to a peer.

Effective with Cisco IOS XE Release 2.1, a peer can still be mapped as explained above. However, the Certificate to ISAKMP Profile Mapping feature enables you to assign an ISAKMP profile to a peer on the basis of the contents of arbitrary fields in the certificate. You are no longer limited to assigning an ISAKMP profile on the basis of the subject name of the certificate. In addition, this feature allows you to assign a group to a peer to which an ISAKMP profile has been assigned.

How Certificate to ISAKMP Profile Mapping Works

Figure 1 illustrates how certificate maps may be attached to ISAKMP profiles and assigned group names.

Figure 1 Certificate Maps Mapped for Profile Group Assignment

A certificate map can be attached to only one ISAKMP profile although an ISAKMP profile can have several certificate maps attached to it.

Certificate maps provide the ability for a certificate to be matched with a given set of criteria. ISAKMP profiles can bind themselves to certificate maps, and if the presented certificate matches the certificate map present in an ISAKMP profile, the peer will be assigned the ISAKMP profile. If the ISAKMP profile contains a client configuration group name, the same group name will be assigned to the peer. This ISAKMP profile information will override the information in the ID_KEY_ID identity or in the first OU field of the certificate.

Assigning an ISAKMP Profile and Group Name to a Peer

To assign an ISAKMP profile to a peer on the basis of arbitrary fields in the certificate, use the match certificate command after the ISAKMP profile has been defined.

To associate a group name with an ISAKMP profile that will be assigned to a peer, use the client configuration group command, also after the ISAKMP profile has been defined.

How to Configure Certificate to ISAKMP Profile Mapping

•Mapping the Certificate to the ISAKMP Profile (required)

•Verifying That the Certificate Has Been Mapped (optional)

•Assigning the Group Name to the Peer (required)

•Monitoring and Maintaining Your Certificate to ISAKMP Profile Mapping (optional)

Mapping the Certificate to the ISAKMP Profile

To map the certificate to the ISAKMP profile, perform the following steps. This configuration will enable you to assign the ISAKMP profile to a peer on the basis of the contents of arbitrary fields in the certificate.

SUMMARY STEPS

1. enable

2. configure terminal

3. crypto isakmp profile profile-name

4. match certificate certificate-map

DETAILED STEPS

Verifying That the Certificate Has Been Mapped

The following show crypto ca certificates command may be used to verify that the subject name of the certificate map has been properly configured.

SUMMARY

1. enable

2. show crypto ca certificates

DETAILED STEPS

Assigning the Group Name to the Peer

To associate a group name with a peer when the peer is mapped to an ISAKMP profile, perform the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. crypto isakmp profile profile-name

4. client configuration group group-name

DETAILED STEPS

Monitoring and Maintaining Your Certificate to ISAKMP Profile Mapping

To monitor and maintain your certificate to ISAKMP profile mapping, you may use the following debug crypto isakmp command.

SUMMARY STEPS

1. enable

2. debug crypto isakmp

DETAILED STEPS

Configuration Examples for Certificate to ISAKMP Profile Mapping

This section contains the following configuration examples:

•Certificates Mapped to the ISAKMP Profile on the Basis of Arbitrary Fields: Example

•Group Name Assigned to a Peer That Is Associated with an ISAKMP Profile: Example

•Mapping a Certificate to an ISAKMP Profile Verification: Example

•Group Name Assigned to a Peer Verification: Example

Certificates Mapped to the ISAKMP Profile on the Basis of Arbitrary Fields: Example

The following configuration example shows that whenever a certificate contains "ou = green," the ISAKMP profile "cert_pro" will be assigned to the peer:

crypto pki certificate map cert_map 10 

 subject-name co ou = green

!

!

crypto isakmp identity dn

crypto isakmp profile cert_pro 

   ca trust-point 2315 

   ca trust-point LaBcA 

   initiate mode aggressive

   match certificate cert_map 

Group Name Assigned to a Peer That Is Associated with an ISAKMP Profile: Example

The following example shows that the group "some_group" is to be associated with a peer that has been assigned an ISAKMP profile:

crypto isakmp profile id_profile 

   ca trust-point 2315

   match identity host domain cisco.com

   client configuration group some_group

Mapping a Certificate to an ISAKMP Profile Verification: Example

The following examples show that a certificate has been mapped to an ISAKMP profile. The examples include the configurations for the responder and initiator, the show command output verifying that the subject name of the certificate map has been configured, and debug command output showing that the certificate has gone through certificate map matching and been matched to the ISAKMP profile.

Responder Configuration

crypto pki certificate map cert_map 10

! The above line is the certificate map definition.

 subject-name co ou = green

! The above line shows that the subject name must have "ou = green."

! 

crypto isakmp profile certpro

! The above line shows that this is the ISAKMP profile that will match if the certificate 
of the peer matches cert_map (shown on third line below).

   ca trust-point 2315

   ca trust-point LaBcA

   match certificate cert_map 

   initiate mode aggressive

Initiator Configuration

crypto ca trustpoint LaBcA

 enrollment url http://10.76.82.20:80/cgi-bin/openscep

 subject-name ou=green,c=IN

! The above line ensures that the subject name "ou = green" is set.

 revocation-check none

show crypto ca certificates Command Output for the Initiator

Router# show crypto ca certificates

Certificate

  Status: Available

  Certificate Serial Number: 21

  Certificate Usage: General Purpose

  Issuer: 

    cn=blue-lab CA

    o=CISCO

    c=IN

  Subject:

    Name: Router1.cisco.com

    c=IN

    ou=green

! The above line is a double check that "ou = green" has been set as the subject name.

    hostname=Router1.cisco.com

  Validity Date: 

    start date: 14:34:30 UTC Mar 31 2004

    end   date: 14:34:30 UTC Apr 1 2009

    renew date: 00:00:00 UTC Jan 1 1970

  Associated Trustpoints: LaBcA

debug crypto isakmp Command Output for the Responder

Router# debug crypto isakmp

6d23h: ISAKMP (0:268435460): received packet from 192.0.0.2 dport 500 sport 500 Global (R) 
MM_KEY_EXCH

6d23h: ISAKMP: Main Mode packet contents (flags 1, len 892):

6d23h:           ID payload

6d23h:             FQDN <Router1.cisco.com> port 500 protocol 17

6d23h:           CERT payload

6d23h:           SIG payload

6d23h:           KEEPALIVE payload

6d23h:           NOTIFY payload

6d23h: ISAKMP:(0:4:HW:2):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH

6d23h: ISAKMP:(0:4:HW:2):Old State = IKE_R_MM4  New State = IKE_R_MM5 

6d23h: ISAKMP:(0:4:HW:2): processing ID payload. message ID = 0

6d23h: ISAKMP (0:268435460): ID payload 

        next-payload : 6

        type         : 2 

        FQDN name    : Router1.cisco.com 

        protocol     : 17 

        port         : 500 

        length       : 28

6d23h: ISAKMP:(0:4:HW:2):: peer matches *none* of the profiles

6d23h: ISAKMP:(0:4:HW:2): processing CERT payload. message ID = 0

6d23h: ISAKMP:(0:4:HW:2): processing a CT_X509_SIGNATURE cert

6d23h: ISAKMP:(0:4:HW:2): peer's pubkey isn't cached

6d23h: ISAKMP:(0:4:HW:2): OU = green

6d23h: ISAKMP:(0:4:HW:2): certificate map matches certpro profile

! The above line shows that the certificate has gone through certificate map matching and 
that it matches the "certpro" profile.

6d23h: ISAKMP:(0:4:HW:2): Trying to re-validate CERT using new profile

6d23h: ISAKMP:(0:4:HW:2): Creating CERT validation list: 2315, LaBcA, 

6d23h: ISAKMP:(0:4:HW:2): CERT validity confirmed.

Group Name Assigned to a Peer Verification: Example

The following configuration and debug output show that a group has been assigned to a peer.

Initiator Configuration

crypto isakmp profile certpro

   ca trust-point 2315

   ca trust-point LaBcA

   match certificate cert_map

   client configuration group new_group

! The statement on the above line will assign the group "new_group" to any peer that 
matches the ISAKMP profile "certpro." 

   initiate mode aggressive 

!

debug crypto isakmp profile Command Output for the Responder

The following debug output example shows that the peer has been matched to the ISAKMP profile named "certpro" and that it has been assigned a group named "new_group."

Router# debug crypto isakmp profile

6d23h: ISAKMP (0:268435461): received packet from 192.0.0.2 dport 500 sport 500 Global (R) 
MM_KEY_EXCH

6d23h: ISAKMP: Main Mode packet contents (flags 1, len 892):

6d23h:           ID payload

6d23h:             FQDN <Router1.cisco.com> port 500 protocol 17

6d23h:           CERT payload

6d23h:           SIG payload

6d23h:           KEEPALIVE payload

6d23h:           NOTIFY payload

6d23h: ISAKMP:(0:5:HW:2):Input = IKE_MESG_FROM_PEER, IKE_MM_EXCH

6d23h: ISAKMP:(0:5:HW:2):Old State = IKE_R_MM4  New State = IKE_R_MM5 

6d23h: ISAKMP:(0:5:HW:2): processing ID payload. message ID = 0

6d23h: ISAKMP (0:268435461): ID payload 

        next-payload : 6

        type         : 2 

        FQDN name    : Router1.cisco.com 

        protocol     : 17 

        port         : 500 

        length       : 28

6d23h: ISAKMP:(0:5:HW:2):: peer matches *none* of the profiles

6d23h: ISAKMP:(0:5:HW:2): processing CERT payload. message ID = 0

6d23h: ISAKMP:(0:5:HW:2): processing a CT_X509_SIGNATURE cert

6d23h: ISAKMP:(0:5:HW:2): peer's pubkey isn't cached

6d23h: ISAKMP:(0:5:HW:2): OU = green

6d23h: ISAKMP:(0:5:HW:2): certificate map matches certpro profile

6d23h: ISAKMP:(0:5:HW:2): Trying to re-validate CERT using new profile

6d23h: ISAKMP:(0:5:HW:2): Creating CERT validation list: 2315, LaBcA, 

6d23h: ISAKMP:(0:5:HW:2): CERT validity confirmed.

6d23h: ISAKMP:(0:5:HW:2):Profile has no keyring, aborting key search

6d23h: ISAKMP:(0:5:HW:2): Profile certpro assigned peer the group named new_group

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for Certificate to ISAKMP Profile Mapping

Table 1 lists the release history for this feature.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XE software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp. An account on Cisco.com is not required.

Note Table 1 lists only the Cisco IOS XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2004-2009 Cisco Systems, Inc. All rights reserved.