From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 6 May 2001 04:40:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 6 May 2001 04:40:30 -0400 Received: from ns.suse.de ([213.95.15.193]:29713 "HELO Cantor.suse.de") by vger.kernel.org with SMTP id ; Sun, 6 May 2001 04:40:11 -0400 Date: Sun, 6 May 2001 10:34:50 +0200 From: Andi Kleen To: dean gaudet Cc: "David S. Miller" , Ben Greear , linux-kernel , Alan Cox , Andi Kleen , Linus Torvalds Subject: Re: [PATCH] arp_filter patch for 2.4.4 kernel. Message-ID: <20010506103450.A29403@gruyere.muc.suse.de> In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from dean-list-linux-kernel@arctic.org on Sat, May 05, 2001 at 03:57:38PM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 05, 2001 at 03:57:38PM -0700, dean gaudet wrote: > also -- isn't it kind of wrong for arp to respond with addresses from > other interfaces? Usually it makes sense, because it increases your chances of successfull communication. IP addresses are owned by the complete host on Linux, not by different interfaces. For some weirder setups (most of them just caused by incorrect routing tables, but also a few legimitate ones; including incoming load balancing via multipath routes) it causes problems, so arpfilter was invented to sync ARP replies with the routing tables as needed. > > what if ip_forward is 0? or if there's some other sort of routing policy > in effect? ARP filter has nothing to do with forwarding. There is magic ARP proxying if linux knows the answer to an ARP request on a different interface, but it's a completely independent thing. -Andi