Subject: Re: Stripping GRE Too Early?
To: Curt Sampson <>
From: None <>
List: tech-net
Date: 01/07/2000 06:55:21
>>It seems that under NetBSD 1.4.1, at least, when you set up a gre tunnel
>>between two machines, the `real' interface that the tunnel's packets pass
>>over is showing de-encapsulated incoming packets to bpf, ipfilter, etc.
>>(Outgoing are shown encapsulated.) Here's an example:
>>16:33:38.755359 > icmp: echo request (gre encap)
>>16:33:38.788769 > icmp: echo reply
>>What's up with this? Does current still do it?
>	bpf sends encapsulated packet to userland.
>	NetBSD 1.4.1 tcpdump(8) skips outer header, if you don't have -v on
>	command line.   If you have -v, it will print like this:
>>16:33:38.755359 > gre > icmp: echo request (gre encap)
>	I think this is a bit confusing that the order is reversed.

	I may be wrong about the above 1.4.1 example; anyway, -v should help