From owner-freebsd-hackers@FreeBSD.ORG Sat Mar 18 05:48:50 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9D45B16A41F for ; Sat, 18 Mar 2006 05:48:50 +0000 (UTC) (envelope-from ray@redshift.com) Received: from mail-fs2.redshift.com (mail-pop.redshift.com [216.228.2.14]) by mx1.FreeBSD.org (Postfix) with ESMTP id 267C643D58 for ; Sat, 18 Mar 2006 05:48:50 +0000 (GMT) (envelope-from ray@redshift.com) Received: (qmail 76873 invoked by uid 89); 18 Mar 2006 05:48:48 -0000 Received: by simscan 1.2.0 ppid: 76869, pid: 76870, t: 0.1419s scanners: attach: 1.2.0 clamav: 0.88/m:36/d:1318 Received: from unknown (HELO workstation) (216.228.19.21) by mail-fs2.redshift.com with SMTP; 18 Mar 2006 05:48:48 -0000 Message-Id: <3.0.1.32.20060317214849.00c00778@pop.redshift.com> X-Mailer: na X-Sender: redshift.com Date: Fri, 17 Mar 2006 21:48:49 -0800 To: Glenn Dawson ,freebsd-hackers@freebsd.org From: ray@redshift.com In-Reply-To: <7.0.1.0.2.20060317205230.057ba948@antimatter.net> References: <3.0.1.32.20060317203432.00bf8a40@pop.redshift.com> <441B09DA.1010902@elischer.org> <200603171502.k2HF2IV3086523@pinky.frank-behrens.de> <20060317151220.GA26987@britannica.bec.de> <441B09DA.1010902@elischer.org> <3.0.1.32.20060317203432.00bf8a40@pop.redshift.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Subject: Re: strange ARP problem X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 18 Mar 2006 05:48:50 -0000 At 08:59 PM 3/17/2006 -0800, Glenn Dawson wrote: | At 08:34 PM 3/17/2006, ray@redshift.com wrote: | >I'm having a strange issue here and thought maybe someone on this list might | >have some ideas. I have tried to figure it out for a couple of days, but no | >luck yet. The problem seems to be around reporting of arp information. | > | >Here is my basic config. I have my workstation (a windows XP box) with 2 IP's | >on a private network segment (both with /24 subnet masks) | > | >192.168.10.250 | >192.168.20.250 | > | >the 10.250 and 20.250 are connected out to a small switch. Also connected to | >that small switch is a mail server as shown below. | > | >[ workstation ] [ mail server ] | >[192.168.10.250]-------[ small ]--------[ 192.168.10.15] | >[192.168.20.250]-------[ switch ]--------[ 192.168.20.15] | > | | > | | > [router 192.168.10.1] | > | | > public IP | > | >10.15 handles SMTP to the public, 20.15 is for admin and POP to/from the | >workstation on 20.250 | > | >Okay, so the problem is that when I fire up the Workstation (it's running | >Windows XP), the arp data for 192.168.20.15 comes back with the incorrect Mac | >address. It ends up with the Mac address for 10.15, instead of 20.15 - which | >keeps the machines from talking correctly. If you delete the ARP table and | >re-arp, then it's perfectly fine from then on. Totally odd. | > | >Then the other night I noticed the following errors (see below) from the mail | >server. It seems to be related, but I can't pin point the source or | >what might | >cause something like this. | > | >Does anyone have any ideas what could be causing this? | > | > > arp: 192.168.10.1 is on fxp0 but got reply from 00:30:48:52:08:03 on bge0 | > > arp: 192.168.20.250 is on bge0 but got reply from 00:e0:81:32:e0:a0 on fxp0 | > > arp: 00:30:48:51:ce:f0 is using my IP address 192.168.20.15! | > > arp: 00:30:48:51:ce:f0 is using my IP address 192.168.20.15! | > > arp: 192.168.10.1 is on fxp0 but got reply from 00:30:48:52:08:03 on bge0 | > > arp: 00:30:48:51:ce:f0 is using my IP address 192.168.20.15! | > > arp: 192.168.10.15 is on lo0 but got reply from 00:30:48:51:ce:f0 on bge0 | > > arp: 192.168.10.1 is on fxp0 but got reply from 00:30:48:52:08:03 on bge0 | > > arp: 192.168.10.15 is on lo0 but got reply from 00:30:48:51:ce:f0 on bge0 | > > arp: 192.168.20.250 is on bge0 but got reply from 00:e0:81:32:e0:a0 on fxp0 | > > arp: 192.168.10.15 is on lo0 but got reply from 00:30:48:51:ce:f0 on bge0 | > > arp: 192.168.10.1 is on fxp0 but got reply from 00:30:48:52:08:03 on bge0 | > | >here is the ifconfig from the mail server: | > | >[ray@mail ray]$ ifconfig | >fxp0: flags=8843 mtu 1500 | > inet 192.168.10.15 netmask 0xffffff00 broadcast 192.168.10.255 | > ether 00:30:48:51:ce:f0 | > media: Ethernet autoselect (100baseTX ) | > status: active | >bge0: flags=8843 mtu 1500 | > options=1b | > inet 192.168.20.15 netmask 0xffffff00 broadcast 192.168.20.255 | > ether 00:30:48:51:ce:f1 | > media: Ethernet autoselect (100baseTX ) | > status: active | >lo0: flags=8049 mtu 16384 | > inet 127.0.0.1 netmask 0xff000000 | > | >If anyone has any idea, please let me know. Thanks! | | This is exactly why it's ill-advised to have two network interfaces | on different networks connected to the same physical network. | | If you actually need two different networks (although from your | description I don't see a reason why you would) then use a single | physical interface and assign it an IP from each network. Or, get a | switch that has VLAN capabilities and keep the two networks separated. | | -Glenn The switch should act as a bridge - so from the standpoint of the computers, shouldn't it effectively be two different networks? In other words, if I ran 20.x across a different switch, would that matter? I've always understood that a switch was something you viewed as basically a bunch of individual little bridges. I can drag out another switch and test that idea and see if the problem goes away. This problem did start when I ran everything through 1 switch - I just didn't think that would any specific negative impact. Thanks for the note back Glenn :-) Ray