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Date:      Fri, 05 Oct 2007 17:31:25 -0600
From:      freebsd@dreamchaser.org
To:        freebsd-questions@freebsd.org
Subject:   tcpdump -- non-local traffic not showing
Message-ID:  <4706C94D.4030206@dreamchaser.org>

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Hi all,

Running 6.1

I'm having trouble seeing packets which are not going to or from the
machine on which tcpdump is running.  Is there something special I
need to do to enable this?  It's my understanding tcpdump puts the
interface in promiscuous mode, and dmesg seems to confirm this.
However I see the following behavior using "tcpdump -fntl -i ed1":

If hosts .x, .y, and .z are all on the same network,
and if tcpdump is running on host a.b.c.x
and on host a.b.c.y I do
  ping a.b.c.x

I see the icmp packets.

But if on host a.b.c.y I do
  ping a.b.c.z

I see nothing.
Does the interface drop packets with a different mac address, even
when supposedly put in promiscuous mode?

Clues?

Thanks for any insights,

Gary



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