From owner-freebsd-questions@FreeBSD.ORG Sat Oct 6 00:03:45 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A7E5E16A46C for ; Sat, 6 Oct 2007 00:03:45 +0000 (UTC) (envelope-from freebsd@dreamchaser.org) Received: from nightmare.dreamchaser.org (nightmare.dreamchaser.org [12.32.36.65]) by mx1.freebsd.org (Postfix) with ESMTP id 2080613C455 for ; Sat, 6 Oct 2007 00:01:25 +0000 (UTC) (envelope-from freebsd@dreamchaser.org) Received: from [12.32.36.67] (freshstart.dreamchaser.org. [12.32.36.67]) by nightmare.dreamchaser.org (8.13.6/8.13.6) with ESMTP id l95NVPrL012417 for ; Fri, 5 Oct 2007 17:31:26 -0600 (MDT) (envelope-from freebsd@dreamchaser.org) Message-ID: <4706C94D.4030206@dreamchaser.org> Date: Fri, 05 Oct 2007 17:31:25 -0600 From: freebsd@dreamchaser.org User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: freebsd-questions@freebsd.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0.2 (nightmare.dreamchaser.org [12.32.36.65]); Fri, 05 Oct 2007 17:31:26 -0600 (MDT) Subject: tcpdump -- non-local traffic not showing X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 06 Oct 2007 00:03:45 -0000 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