From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergey Popovich Subject: Incorrect ARP behavior when multiple/none IPv4 address assigned to interface Date: Tue, 23 Oct 2012 14:28:17 +0300 Message-ID: <50867F51.3030500@mail.ru> Reply-To: Sergey Popovich Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from fallback3.mail.ru ([94.100.176.58]:42445 "EHLO fallback3.mail.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752440Ab2JWLfm (ORCPT ); Tue, 23 Oct 2012 07:35:42 -0400 Received: from smtp15.mail.ru (smtp15.mail.ru [94.100.176.133]) by fallback3.mail.ru (mPOP.Fallback_MX) with ESMTP id 2F86EC3C5505 for ; Tue, 23 Oct 2012 15:28:55 +0400 (MSK) Received: from [195.234.68.4] (port=33347 helo=tuxracer.localdomain) by smtp15.mail.ru with esmtpa (envelope-from ) id 1TQcev-00031h-Cs for netdev@vger.kernel.org; Tue, 23 Oct 2012 15:28:33 +0400 Sender: netdev-owner@vger.kernel.org List-ID: Hello! We have following setup: ------------------------ PC1 | | ip: 10.0.1.2/24 | | Linux Router (3.7-rc2) gw: 10.0.1.1 |--------eth0-| Lo0: 10.10.10.10/32 | Lo255: 10.0.1.1/24 PC2 |--------eth1-| 10.0.2.1/24 ip: 10.0.1.3/24 | | eth[0-2]: no ip address gw: 10.0.1.1 | | ip route 10.0.1.2/32 dev eth0 src 10.0.1.1 +-| ip route 10.0.1.3/32 dev eth1 src 10.0.1.1 | | ip route 10.0.2.2/32 dev eth2 src 10.0.2.1 PC3 |-----eth2--+ ip: 10.0.2.2/24 | gw: 10.0.2.1 | Problem with ARP Requests sent with incorrect source address (10.10.10.10 instead of 10.0.1.1): # tcpdump -vv -ieth0 -s1500 -nnpe 'arp' 13:28:57.395181 08:00:27:3b:63:ae > 0a:00:27:00:00:00, ethertype ARP (0x0806), length 42: Ethernet (len 6),. IPv4 (len 4), Request who-has 10.0.1.2 tell 10.10.10.10, length 28 13:28:58.395257 08:00:27:3b:63:ae > 0a:00:27:00:00:00, ethertype ARP (0x0806), length 42: Ethernet (len 6),. IPv4 (len 4), Request who-has 10.0.1.2 tell 10.10.10.10, length 28 13:28:59.395207 08:00:27:3b:63:ae > 0a:00:27:00:00:00, ethertype ARP (0x0806), length 42: Ethernet (len 6),. IPv4 (len 4), Request who-has 10.0.1.2 tell 10.10.10.10, length 28 13:29:01.393739 08:00:27:3b:63:ae > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6),. IPv4 (len 4), Request who-has 10.0.1.2 tell 10.0.1.1, length 28 13:29:01.393862 0a:00:27:00:00:00 > 08:00:27:3b:63:ae, ethertype ARP (0x0806), length 60: Ethernet (len 6),. IPv4 (len 4), Reply 10.0.1.2 is-at 0a:00:27:00:00:00, length 46 Detailed information about this (and other, that triggers same case with ARP) network topology usage in real world can be found at https://bugzilla.kernel.org/show_bug.cgi?id=49311 Sorry for early bug report. -- SP5474-RIPE Sergey Popovich