From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: TCP keepalives ignored by kernel when the contain timestamps Date: Fri, 10 Jun 2011 18:17:01 +0200 Message-ID: <1307722621.4044.17.camel@edumazet-laptop> References: <4DF0E638.2010506@uth.tmc.edu> <1307714177.4044.4.camel@edumazet-laptop> <4DF233CE.5020000@uth.tmc.edu> <4DF24154.3060505@uth.tmc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Charles Bearden Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:63470 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750885Ab1FJQRF (ORCPT ); Fri, 10 Jun 2011 12:17:05 -0400 Received: by wya21 with SMTP id 21so1977034wya.19 for ; Fri, 10 Jun 2011 09:17:04 -0700 (PDT) In-Reply-To: <4DF24154.3060505@uth.tmc.edu> Sender: netdev-owner@vger.kernel.org List-ID: Le vendredi 10 juin 2011 =C3=A0 11:07 -0500, Charles Bearden a =C3=A9cr= it : > You are correct: the checksums in the keepalives are broken, though t= hey are=20 > correct in the other segments from the Win2008 server. I have updated= the pastes=20 > linked to above with 'tcpdump -v' output. I apologize for missing tha= t problem=20 > the first time around. Hmm, maybe its OK : If checksums are offloaded to NIC, tcpdump 'lies' telling checksum is not OK, since tcpdump get a copy of the packet before being handled by the NIC. You should take a tcpdump on the receiving machine (the machine that apparently doesnt react to the keepalive probes)