How can we see the packets tunneled inside the GRE tunnel?
Environment : This article is valid for all Aruba controllers, and software versions.
Symptoms : We can see the GRE encapsulated in the wireshark but we cannot decrypt the contents.
Cause : By default, Aruba uses GRE mode 0 which doesn't allow wireshark to decrypt the contents.
Solution : Set the GRE mode to 25944 on both the ends of the tunnel:
interface tunnel 2
description "Tunnel Interface"
tunnel source 10.1.1.3
tunnel mode gre 25944
tunnel destination 10.1.1.2
tunnel keepalive 5 3
tunnel vlan 2
After this, the contents of the GRE are visible in the Wireshark:
Here we can see the contents in the wireshark as ICMP.
Related Links : http://tools.ietf.org/search/rfc1701