Subject: bin/34172: tcpdump doesn't catch any non-IP packet on gre(4) interface
To: None <firstname.lastname@example.org, email@example.com>
From: None <firstname.lastname@example.org>
Date: 08/09/2006 09:10:00
>Synopsis: tcpdump doesn't catch any non-IP packet on gre(4) interface
>Arrival-Date: Wed Aug 09 09:10:00 +0000 2006
>Originator: Mihai Chelaru
>Release: NetBSD 3.99.20
System: NetBSD mpls.girsa.ro 3.99.20 NetBSD 3.99.20 (ayame-mpls) #0: Tue Aug 8 12:22:30 EEST 2006 email@example.com:/usr/src/sys/arch/i386/compile/ayame-mpls i386
I created a gre tunnel in order to send some MPLS unicast frames over it. They are passing fine but
tcpdump can't catch any of it.
mpls# tcpdump -l -n -vvv -i gre0 ether proto 0x8847
tcpdump: expression rejects all packets
mpls# tcpdump -l -n -vvv -O -i gre0 ether proto 0x8847
tcpdump: listening on gre0, link-type NULL (BSD loopback), capture size 96 bytes
0 packets captured
14 packets received by filter
0 packets dropped by kernel
During this I left an icmp ping that is encapsulated into MPLS on a router connected via tunnel gre0.
The only ether proto I saw working was 0x0800 (IP).