From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: Q: bad routing table cache entries Date: Tue, 12 Jan 2016 16:52:39 +0100 Message-ID: <56952147.80201@stressinduktion.org> References: <5682665A.7090102@list.ru> <56951D1D.5080602@stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: Stas Sergeev , netdev Return-path: Received: from out4-smtp.messagingengine.com ([66.111.4.28]:52181 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753323AbcALPwl (ORCPT ); Tue, 12 Jan 2016 10:52:41 -0500 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id B111B20770 for ; Tue, 12 Jan 2016 10:52:40 -0500 (EST) In-Reply-To: <56951D1D.5080602@stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-ID: On 12.01.2016 16:34, Hannes Frederic Sowa wrote: > On 29.12.2015 11:54, Stas Sergeev wrote: >> Hello. >> >> I was hitting a strange problem when some internet hosts >> suddenly stops responding until I reboot. ping to these >> host gives "Destination Host Unreachable". After the >> initial confusion, I've finally got to >> ip route get >> and got something quite strange. >> >> >> Example for GOOD address (the one that I can ping): >> >> ip route get 91.189.89.237 >> 91.189.89.237 via 192.168.8.1 dev eth0 src 192.168.10.202 >> cache >> >> >> Example for BAD address (the one that stopped responding): >> >> ip route get 91.189.89.238 >> 91.189.89.238 via 192.168.0.1 dev eth0 src 192.168.10.202 >> cache > > I tried to understand this thread and now wonder why this redirect route > isn't there always. Can you please summarize again why this shouldn't > happen? It looks totally fine to me from the configuration of your > router and the subnet masks. Just an addendum: In IPv6 a redirect is seen as a notification telling hosts, this new address is on the same link as you. I think this semantic is the same for IPv4, so we are informing you that in essence you are getting a /32 route installed to your new interface and can do link layer resolving of the new host. I do think this is valid and fine. Bye, Hannes