Dear experts I want to test site to site VPN on GNS3 with Cisco 2600 Router, 2691, 3600, and 3700 and can't support ISAKMP support and need to update the software on its IOS and I am not able to such configuration on GNS3. Can any please advise what to do.

Thanks for the support in advance

You have to add to GNS3 any image that supports crypto. Usually these images have "k9" somewhere in the name of image; most frequent phrases are: "advsecurityk9", "adventerprisek9", "advipservicesk9", "ik9s", "ik9os3", "jk9s", "jk9o3s", "telcoentk9".

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Is there a bug on the GNS3? I am trying to create a site to site vpn on serial interfaces using k9 images of 7200's but I can't seem to ping and UP the interface that are supposed to be tunnelling.

Please guide me on what logs do I need to provide for you to see what is wrong?

1. You DO NOT have to use k9 images just for creating tunnel interfaces - you can do it even on images that do not support crypto. It is called GRE tunnelling.
2. Crypto is required for IPSec, which is used to ecnrypt traffic between two routers - but of course usually IPSec policies are applied on Tunnel interfaces.

So what problem do you have? With GRE tunnelling or with encrypting traffic on tunnel interfaces (IPSesc/ISAKMP problems)?

Good example about creating pure GRE tunnel are at https://supportforums.cisco.com/documen ... gre-tunnel and for complete GRE tunnel encrypted by IPSec look at http://www.firewall.cx/cisco-technical- ... ipsec.html
Of course, there are tons of documentation at Cisco site covering both GRE and IPSec.

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If you can see any inaccuracies or other language-related mistakes in my post(s), please forgive me - English is not my native language