But even if I capture with "-i any" i see only 4 GTP packets: The ECHO Req/Resp and the PDP-C create Req/Resp. The are no GTP encapsulated ICMP/payload messages.
I have attached a cap with an example of this. Also, like I mentioned, nothing happens if I pause the ggsn with ctrl-z. The ping should have been interrupted by this, I think...
Not sure what to make of this. It seems I can't get GTP-U to work at all.