Wireshark · Wireshark-users: Re: [Wireshark-users] How to decode nested l2tp traffic?

[Patrick Klos <patrick@xxxxxxxx>]

Joan wrote:
> I am trying to extract the data transmitted into a l2tp tunnel, I am 
> running thsark/tcpdump in the tunnel terminator. What I am using so 
> far is this (4291 is the tunnel number):
>   tcpdump -n -i eth3.800 "udp port 1701 && udp[8:2] & 0x80ff == 0x0002 
> && udp[10:2] == 4291" 
>
> I took the filter line from here 
> http://networkingbodges.blogspot.com.es/2012/11/tshark-one-liners.html
>
> The problem is that I would like to inspect the traffic inside the 
> tunnel, but I could'nt find a reference on this.
>
> Any clues?

Can you share a pcap file?  I could run it through PacketView (which 
de-tunnels L2TP) and see if it helps??

Patrick Klos
Klos Technologies, Inc.