Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 13 Jul 2002 12:23:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 13 Jul 2002 12:23:34 -0400 Received: from tmr-02.dsl.thebiz.net ([216.238.38.204]:53765 "EHLO gatekeeper.tmr.com") by vger.kernel.org with ESMTP id ; Sat, 13 Jul 2002 12:23:33 -0400 Date: Sat, 13 Jul 2002 12:21:10 -0400 (EDT) From: Bill Davidsen To: Linux-Kernel Mailing List Subject: [BUG?] unwanted proxy arp in 2.4.19-pre10 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1808 Lines: 44 I think there's a bug, or at least unexpected behaviour in 2.4.19-pre10 regarding ARP replies. I am getting multiple arp-replies to a who-has request, and there seems to be no check in arp.c to verify that the interface used for an arp reply actually has that address or has proxy set. Details: node_A 192.168.230.1 router | \ 192.168.231.127 | \ 192.168.0.0/16 access | bridge / | \ / | \ / 192.168.230.4 192.168.231.4 \ / node_B When node_A does an arp request, who-has 192.168.230.4, it gets a correct answer from the NIC with that IP. It also gets a reply from the NIC on the 192.168.231 IP, because the ARP broadcast was bridged to that NIC and there's no check to see if that NIC actually has the IP in question. Since the networks are bridged for the moment, the 2nd reply also arrives, later, and winds up in the arp table on node_A, where it results in all traffic going through the bridge to the wrong NIC. In the absense of the proxy_arp flag, I would not expect that reply, the IP is not on that NIC. Before I "fix" that, is this intended behaviour for some reason? Will I break something if I add check logic? Is there something in /proc/sys/net/ipv4 I missed which will avoid this response? -- bill davidsen CTO, TMR Associates, Inc Doing interesting things with little computers since 1979. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/