From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tore Anderson Subject: [PATCH] Improve cached ECMP documentation Date: Wed, 07 Mar 2007 13:37:44 +0100 Message-ID: <45EEB218.8000804@linpro.no> References: <20070307073932.GA1675@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Jarek Poplawski To: "David S. Miller" Return-path: Received: from mailhub.linpro.no ([213.236.139.167]:42138 "EHLO mailhub.linpro.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965133AbXCGMhp (ORCPT ); Wed, 7 Mar 2007 07:37:45 -0500 In-Reply-To: <20070307073932.GA1675@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Document that equal-cost multipath routing with caching does not work for forwarded packets. Signed-Off-By: Tore Anderson --- * Jarek Poplawski > It is probably one of the most often asked questions > on the LARTC, so I'd suggest to look at its archives. > > [...] > > Multipath with caching doesn't work with forwarding. Well, I did look at LARTC's archives (and again after reading your mail), still couldn't find anything. Sorry for bothering you, though. When I disabled the support it worked just fine (no need for iptables CONNMARK trickery or any of Julian's patches), so thanks for your help! Anyway, it strikes me as a bit odd that this feature is found under CONFIG_IP_ADVANCED_ROUTER when it doesn't work for routers. That could at least be better documented - here's a patch to do just that. --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -124,6 +124,10 @@ config IP_ROUTE_MULTIPATH_CACHED routing cache. If you say Y here, alternative routes are cached and on cache lookup a route is chosen in a configurable fashion. + Be warned that this feature does not work for forwarded packets, + and that enabling it will break equal cost multipath routing for + forwarded traffic. + If unsure, say N. config IP_ROUTE_MULTIPATH_RR