From owner-freebsd-net@FreeBSD.ORG Mon Jul 2 16:47:28 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 48B7816A421 for ; Mon, 2 Jul 2007 16:47:28 +0000 (UTC) (envelope-from fox@verio.net) Received: from dfw-smtpout1.email.verio.net (dfw-smtpout1.email.verio.net [129.250.36.41]) by mx1.freebsd.org (Postfix) with ESMTP id 1C99213C4BB for ; Mon, 2 Jul 2007 16:47:28 +0000 (UTC) (envelope-from fox@verio.net) Received: from [129.250.36.63] (helo=dfw-mmp3.email.verio.net) by dfw-smtpout1.email.verio.net with esmtp id 1I5P3f-00043V-HN for freebsd-net@freebsd.org; Mon, 02 Jul 2007 16:47:27 +0000 Received: from [129.250.40.241] (helo=limbo.int.dllstx01.us.it.verio.net) by dfw-mmp3.email.verio.net with esmtp id 1I5P3f-0007LS-D7 for freebsd-net@freebsd.org; Mon, 02 Jul 2007 16:47:27 +0000 Received: by limbo.int.dllstx01.us.it.verio.net (Postfix, from userid 1000) id A257B8E296; Mon, 2 Jul 2007 11:47:26 -0500 (CDT) Date: Mon, 2 Jul 2007 11:47:26 -0500 From: David DeSimone To: freebsd-net@freebsd.org Message-ID: <20070702164726.GA31982@verio.net> Mail-Followup-To: freebsd-net@freebsd.org References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; x-action=pgp-signed Content-Disposition: inline In-Reply-To: Precedence: bulk User-Agent: Mutt/1.5.9i Subject: Re: fxp(4) not responding to arp requests (aliases) X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Jul 2007 16:47:28 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Eduardo Meyer wrote: > > When a host who is talking to be deletes its arp entry which has my IP > address, communication goes down, and fxp2 never replies to arp > requests. Completly ignores arp, in fact. Your premise is that the fxp does not respond to arp request, but your example does not show an arp request is being received. > On host2: > > # arp -d 200.X.Y.5 I presume that host2 has IP 200.X.Y.6 and host1 has IP 200.X.Y.5, since you didn't say. > On host1: > > # tcpdump -n -v -i fxp2 arp > tcpdump: listening on fxp2, link-type EN10MB (Ethernet), capture size 96 bytes > > And nothing happens. Is host2 trying to send us traffic? You did not say. Presumably if host2 is trying to send traffic to host1, you should see this: 12:41:43.932590 arp who-has 200.X.Y.5 tell 200.X.Y.6 12:41:44.932590 arp who-has 200.X.Y.5 tell 200.X.Y.6 12:41:45.932590 arp who-has 200.X.Y.5 tell 200.X.Y.6 In other words you should see a repeated arp request with no reply. Are you suggesting that the interface is simply not receiving broadcasts? > On host1 I cycle fxp2 up/down: > > # ifconfig fxp2 down && ifconfig fxp2 up > > And on host1 immediately I see: > > 12:41:08.860484 arp who-has 200.X.Y.6 tell 200.X.Y.5 > 12:41:08.862898 arp reply 200.X.Y.6 is-at 00:11:d8:52:04:fb This doesn't look like host1 is suddenly receiving and replying to an arp request. Instead, it is suddenly sending out an arp request for another host. Why would it do that? I thought host1 was trying to receive some traffic, not send. > And on host2 immediately I see > > 12:41:42.932590 arp who-has 200.X.Y.5 tell 200.X.Y.7 > 12:41:57.515735 arp reply 200.X.Y.5 is-at 00:50:8b:be:64:a4 This is not even the same arp request/reply, so I am not sure what you are pointing out here. Was host2 supposed to be asking for host1's ARP all this time but it never got around to asking until just now? That seems to imply a problem with host2, instead of host1. Also where did this 200.X.Y.7 IP come from? I thought there were only two hosts here. Maybe you could present a more complete description of which host is attempting to send where, and what both hosts see, at the exact same time. - -- David DeSimone == Network Admin == fox@verio.net "It took me fifteen years to discover that I had no talent for writing, but I couldn't give it up because by that time I was too famous. -- Robert Benchley -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFGiSweFSrKRjX5eCoRAspkAJ9KAntcyTAY7YP9tR+R2IKzK18N0gCglbeM SWcASCZyLL/HFKptVjgjfgU= =hpaO -----END PGP SIGNATURE-----