From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Siddharth Taneja" Subject: Scatter gather and TCP MD5 Date: Tue, 31 Jul 2007 03:17:25 -0700 Message-ID: <526ad3230707310317p537d6cfdj2820a0ffe77c059b@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from py-out-1112.google.com ([64.233.166.182]:2997 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757631AbXGaKR1 (ORCPT ); Tue, 31 Jul 2007 06:17:27 -0400 Received: by py-out-1112.google.com with SMTP id d32so3219199pye for ; Tue, 31 Jul 2007 03:17:26 -0700 (PDT) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hello, I am using a vanilla 2.6.22.1 kernel and I see the same kind of problem as had been mentioned some time back on this list http://lkml.org/lkml/2007/5/22/45 The issue is essentially that with the MD5 option enabled for the specific TCP connection, the SYN and SYN-ACKS are passed ok and the connection establishes fine, but the other end (a cisco router) complains about incorrect MD5 signatures on any other message that is sent after this. Setting the scatter-gather offloading option to off on the NIC seems to correct this problem. Recently I had seen a checkin (as a response to the problem mentioned in the above link) where the TSO option was turned off to make MD5 work (my kernel has that fix). Is a similar solution needed here too? This is the information about my system: > uname -a Linux stdalone 2.6.22.1 #1 SMP Mon Jul 23 20:15:21 PDT 2007 i686 i686 i386 GNU/Linux > ethtool -i eth0 driver: e1000 version: 7.3.20-k2 firmware-version: N/A bus-info: 0000:01:0a.0 > ethtool -k eth0 Offload parameters for eth0: rx-checksumming: on tx-checksumming: on scatter-gather: off tcp segmentation offload: off Thanks for your help. Siddharth PS: I would like to be CC'ed on the reply to this email. Thanks.