Potential Problem with Site-to-Site IPsec Tunnel on Cisco ASA Appliances

Debugging Messages for Site-to-Site IPsec Tunnel Issue

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Question

You are trying to set up a site-to-site IPsec tunnel between two Cisco ASA adaptive security appliances, but you are not able to pass traffic.

You try to troubleshoot the issue by enabling debug crypto isakmp and see the following messages: CiscoASA# debug crypto isakmp - [IKEv1]: Group = 209.165.200.231, IP = 209.165.200.231, Tunnel RejecteD.

Conflicting protocols specified by tunnel-group and group-policy [IKEv1]: Group = 209.165.200.231, IP = 209.165.200.231, QM FSM error (P2 struct &0xb0cf31e8, mess id 0x97d965e5)! [IKEv1]: Group = 209.165.200.231, IP = 209.165.200.231, Removing peer from correlator table failed, no match! What could be the potential problem?

Answers

Explanations

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A. B. C. D. E.

C.

The error messages indicate that there is a problem with the configuration of the site-to-site IPsec tunnel between the two Cisco ASA adaptive security appliances. The debug crypto isakmp command was used to gather information about the issue. The following messages were generated:

  • [IKEv1]: Group = 209.165.200.231, IP = 209.165.200.231, Tunnel Rejected.
  • Conflicting protocols specified by tunnel-group and group-policy.
  • [IKEv1]: Group = 209.165.200.231, IP = 209.165.200.231, QM FSM error (P2 struct &0xb0cf31e8, mess id 0x97d965e5)!
  • [IKEv1]: Group = 209.165.200.231, IP = 209.165.200.231, Removing peer from correlator table failed, no match!

Based on this information, it is possible to identify the potential problem with the site-to-site IPsec tunnel configuration. The error message "Conflicting protocols specified by tunnel-group and group-policy" suggests that there is a mismatch between the tunnel-group and the group-policy configuration.

The tunnel-group specifies the remote endpoint of the IPsec tunnel, and the group-policy specifies the configuration settings for the IPsec tunnel. It is important that these two configurations match in terms of the protocols and settings specified.

The answers provided in the question suggest the following potential problems:

A. The policy group mapped to the site-to-site tunnel group is configured to use both IPsec and SSL VPN tunnels. B. The policy group mapped to the site-to-site tunnel group is configured to use both IPsec and L2TP over IPsec tunnels. C. The policy group mapped to the site-to-site tunnel group is configured to just use the SSL VPN tunnel. D. The site-to-site tunnel group is configured to use both IPsec and L2TP over IPsec tunnels. E. The site-to-site tunnel group is configured to just use the SSL VPN tunnel.

Based on the error message, it is most likely that the problem is related to the group-policy configuration. Option A and B suggest that the policy group mapped to the site-to-site tunnel group is configured to use both IPsec and SSL VPN or L2TP over IPsec tunnels. This could cause a conflict with the IPsec tunnel configuration and cause the tunnel to be rejected. Option C suggests that the policy group is configured to just use the SSL VPN tunnel, which is not related to the site-to-site IPsec tunnel configuration, so this is unlikely to be the cause of the problem. Option D suggests that the site-to-site tunnel group is configured to use both IPsec and L2TP over IPsec tunnels, which could cause a conflict with the IPsec tunnel configuration and cause the tunnel to be rejected. Option E suggests that the site-to-site tunnel group is configured to just use the SSL VPN tunnel, which is not related to the site-to-site IPsec tunnel configuration, so this is unlikely to be the cause of the problem.

Therefore, the most likely potential problem is that the policy group mapped to the site-to-site tunnel group is configured to use both IPsec and SSL VPN or L2TP over IPsec tunnels. The configuration should be reviewed to ensure that the protocols and settings specified in the tunnel-group and the group-policy match.