From mboxrd@z Thu Jan 1 00:00:00 1970 From: Flavio Leitner Subject: Re: Unable to flush ICMP redirect routes in kernel 3.0+ Date: Wed, 16 Nov 2011 22:33:30 -0200 Message-ID: <20111116223330.08de9e52@asterix.rh> References: <4EC2CA52.6020104@icdsoft.com> <1321391355.2602.0.camel@edumazet-laptop> <4EC439F2.3080809@icdsoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Ivan Zahariev Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2734 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754073Ab1KQAdf convert rfc822-to-8bit (ORCPT ); Wed, 16 Nov 2011 19:33:35 -0500 In-Reply-To: <4EC439F2.3080809@icdsoft.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 17 Nov 2011 00:32:18 +0200 Ivan Zahariev wrote: > On 11/15/2011 11:09 PM, Eric Dumazet wrote: > > Le mardi 15 novembre 2011 =C3=A0 22:23 +0200, Ivan Zahariev a =C3=A9= crit : > >> Hello, > >> > >> We have changed nothing in our network infrastructure but only > >> upgraded from Linux kernel 2.6.36.2 to 3.0.3. Here is the problem > >> we are experiencing: > >> > >> ICMP redirected routes are cached forever, and they can be cleared > >> only by a reboot. > >>=20 > ### (bug #1) even though we flushed the route cache, the = =20 > route resurrects from somewhere; even without making any TCP requests > ### this time what "ip" returns is consistent with the real > (incorrect) routing behavior of machine5 > root@machine5:~# ip route flush cache > root@machine5:~# ip route list cache match 8.8.4.4 > root@machine5:~# ip route get 8.8.4.4 > 8.8.4.4 via 192.168.0.120 dev eth0 src 192.168.0.244 > cache ipid 0x303a >=20 > ### only a reboot clears the cached routes IIRC, the cache flush doesn't affect the inetpeer where the redirected gateway is now stored, so even after flushing the route cache, the inetpeer will restore the old info later. fbl