From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Jarosch Subject: TCP connection stalls under 2.6.24.7 Date: Fri, 4 Jul 2008 16:54:14 +0200 Message-ID: <200807041654.15591.thomas.jarosch@intra2net.com> References: <47EA0DAB.7080205@securenet.de> <47F08A52.9070802@securenet.de> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Patrick McHardy , Jozsef Kadlecsik , Sven Riedel To: Netfilter Developer Mailing List Return-path: Received: from rs02.intra2net.com ([81.169.173.116]:59873 "EHLO rs02.intra2net.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753468AbYGDOyT (ORCPT ); Fri, 4 Jul 2008 10:54:19 -0400 In-Reply-To: <47F08A52.9070802@securenet.de> Content-Disposition: inline Sender: netfilter-devel-owner@vger.kernel.org List-ID: Hello together, we upgraded from kernel 2.6.23.16 to 2.6.24.7 and are now seeing stalling (smtp) TCP connections on two boxes. We still have the old kernel on a "rescue" partition. If I boot it up, the connections work immediately. The connection work fine if the transmitted data is smaller than ~220kb, so you still can send small messages. I've sent a tcpdump to Patrick in private as it contained sensitive information. The picture is similar to Sven's issue reported backed in march: Some ACK packets are missing (as if the remote side never sent them). I downgraded the box to 2.6.24 to make sure it was not caused by any -stable patch. Same thing. Did any default TCP settings change from 2.6.23.16 to 2.6.24? I also tried to disable path MTU discovery, TCP window scaling and lowered the MTU of the ppp0 interface to 1400 (DSL connection). This had no visible effect. @Sven: Were you able to test 2.6.24.2? Patrick suggested to enable nf_conntrack_log_invalid. I enabled it via "echo 255 > /proc/sys/net/netfilter/nf_conntrack_log_invalid" but that change didn't print anything to syslog. Any ideas? Have a nice weekend, Thomas