Tuesday, May 8, 2012

Cisco to Cisco IPsec-manual Decrypt packets - Part 2

Now let's get into decrypting ICMP packets between R1 and R2.

First let's capture some packets between R1 and R2.
  • Right click on the line between R1 and R2
  • Choose R1 f1/0 
  • Click "OK"

Cisco to Cisco IPsec-manual Decrypt packets - Part 1

We will split this blogtorial into 2 parts. Part 1 will concentrate on how to setup up the IPsec-manual tunnel and Part 2 will concentrate on how to decrypt the traffic between the two VPN end points. Reason we are setting up a ipsec-manual instead of a ipsec-isakmp VPN is because we cannot get the IPsec session keys to decrypt the packet if isakmp is used.

Consider this simple 2 router topology and let's get started.