From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hasso Tepper Subject: Re: icmp_unreachable uses wrong ip Date: Tue, 3 May 2005 09:44:48 +0300 Message-ID: <200505030944.49175.hasso@estpak.ee> References: <1115040079.5620.11.camel@jeroens.office.netland.nl> <200505022038.22014.hasso@estpak.ee> <4276A400.2050306@trash.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: "J. Simonetti" , netdev@oss.sgi.com Return-path: To: Patrick McHardy In-Reply-To: <4276A400.2050306@trash.net> Content-Disposition: inline Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Patrick McHardy wrote: > Hasso Tepper wrote: > > Patrick McHardy wrote: > >>Why can't you simply add the prefered source address to the route? > > > > Because I don't know what it is. Router A knows what's the best path > > from router A to router B, but he can't know (at least in cases where > > there are more than 1 path between them) what's the best path from > > router B to router A. Therefore you can=E4t say which one is incoming > > interface in router A for traffic from router B. And even if you know > > it in some moment, topology might change in next moment (dynamic > > routing) etc. > > Your patch can't guarantee that the address used is the same that was > used as nexthop by the previous hop in the path when multiple addresses > are configured on the incoming interface. So I don't think it achieves > much of your goal of making debugging complicated topologies easier. At first I don't care what was used as nexthop. I want to know which=20 physical link was used. Having multiple addresses in the same link is mor= e=20 corner case in core network anyway. And can you explain what theoretical possibilities router has to obtain i= nfo=20 what address was used as nexthop by neighbour? regards, --=20 Hasso Tepper Elion Enterprises Ltd. WAN administrator