From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?S3J6eXN6dG9mIE9sxJlkemtp?= Subject: Re: 2.6.34: Problem with UDP traffic on lo + poll(?) Date: Mon, 06 Sep 2010 22:44:33 +0200 Message-ID: <4C8552B1.8020806@ans.pl> References: <1283802132.2585.4.camel@edumazet-laptop> <4C854737.5040503@ans.pl> <1283804955.2585.12.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from bizon.gios.gov.pl ([195.187.34.71]:40826 "EHLO bizon.gios.gov.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751669Ab0IFUoh (ORCPT ); Mon, 6 Sep 2010 16:44:37 -0400 In-Reply-To: <1283804955.2585.12.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: On 2010-09-06 22:29, Eric Dumazet wrote: > Le lundi 06 septembre 2010 =C3=A0 21:55 +0200, Krzysztof Ol=C4=99dzki= a =C3=A9crit : > >> Yes, conntrack is one of possibilities. However, this problem only >> manifests on 2.6.34 and never on 2.6.31 where iptables and conntrack >> configurations are identically. And of course, each time it is a >> different port. >> >> Please also note that this problem only exists when communication is >> handled over a loopback interface - I'm not able to trigger this fro= m a >> remote host even if I run the test on two hosts (local& remote) >> simultaneously. >> > > No particular error shown in "netstat -s" ? No... :( Udp: 8542243 packets received 489605 packets to unknown port received. 1 packet receive errors 4254527 packets sent RcvbufErrors: 1 > port randomization on UDP changed in the past, and conntracking chang= ed > a bit too ;) I know but AFAIR all important changs were alredy included in 2.6.31.=20 And again: there is no problem in quering DNS from a remote host: [client 2.6.24.6] <-ethernet-> [server 2.6.34.6] BTW: I have been able to reproduce this problem on a different, less=20 critical host after upgrading its kernel to 2.6.34.6. Unfortunately I'm= =20 still not able to do in on my lab environment. :( Anyway, I'll try to=20 catch "conntrack -E" output and see what conntrack thinks about such=20 packets. Best regards, Krzysztof Ol=C4=99dzki