From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Heffner Subject: [PATCH 0/2] [iputils] MTU discovery changes Date: Fri, 23 Mar 2007 20:46:25 -0400 Message-ID: <460474E1.9070805@psc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev To: YOSHIFUJI Hideaki Return-path: Received: from mailer2.psc.edu ([128.182.66.106]:54572 "EHLO mailer2.psc.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992642AbXCXAqd (ORCPT ); Fri, 23 Mar 2007 20:46:33 -0400 Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org These add some changes that make tracepath a little more useful for diagnosing MTU issues. The length flag helps distinguish between MTU black holes and other types of black holes by allowing you to vary the probe packet lengths. Using PMTUDISC_PROBE gives you the same results on each run without having to flush the route cache, so you can see where MTU changes in the path actually occur. The PMTUDISC_PROBE patch goes in should be conditional on whether the corresponding kernel patch (just sent) goes in. -John