Troubleshooting IPsec Site-to-Site VPNs in Cisco IOS

When you implement a new VPN, there may be a problem or two. So, let’s walk through the verification of the tunnel, and if we discover it not working, I will show you some of my favorite commands to assist in the troubleshooting process.

Let’s first of all verify our configuration so that we can confirm that what we have running on the router is what we configured, starting with Example 7-4.

Example 7-4 Verifying the IPsec Configuration

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! This verifies the IKEv1 Phase 1 policy or policies in place.   The lower! the number of the policy, the higher its priority.R1# show crypto isakmp policyGlobal IKEv1 policyProtection suite of priority 1        encryption algorithm:   AES ...

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