From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262186AbTHTUKh (ORCPT ); Wed, 20 Aug 2003 16:10:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262206AbTHTUKh (ORCPT ); Wed, 20 Aug 2003 16:10:37 -0400 Received: from granite.aspectgroup.co.uk ([212.187.249.254]:19185 "EHLO letters.pc.aspectgroup.co.uk") by vger.kernel.org with ESMTP id S262186AbTHTUKb (ORCPT ); Wed, 20 Aug 2003 16:10:31 -0400 Message-ID: <353568DCBAE06148B70767C1B1A93E625EAB66@post.pc.aspectgroup.co.uk> From: Richard Underwood To: "'David S. Miller'" , Bill Davidsen Cc: dang@fprintf.net, alan@lxorguk.ukuu.org.uk, Richard Underwood , skraw@ithnet.com, willy@w.ods.org, carlosev@newipnet.com, lamont@scriptkiddie.org, bloemsaa@xs4all.nl, marcelo@conectiva.com.br, netdev@oss.sgi.com, linux-net@vger.kernel.org, layes@loran.com, torvalds@osdl.org, linux-kernel@vger.kernel.org Subject: RE: [2.4 PATCH] bugfix: ARP respond on all devices Date: Wed, 20 Aug 2003 21:10:23 +0100 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2656.59) Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org David S. Miller wrote: > > BTW, another thing which makes the source address selection for > outgoing ARPs a real touchy area is the following. Some weird > configurations actually respond with different ARP answers based upon > the source address in the ARP request. You can ask Julian Anastasov > about such (arguably pathological) setups. > *smirk* How horrible. I'm not sure you should be proud of supporting this, and certainly not proud of only half-supporting it. It wouldn't work reliably as things are now as packets will always follow the ARP reply generated by the very first packet. If you want to facilitate this sort of network, you'd need to cache an ARP reply for an IP number against BOTH the Interface AND the interface address used as the source of the ARP request. Only then could you guarantee that packets go to the correct IP number out of the correct interface based on their source address. Richard