From owner-freebsd-net@FreeBSD.ORG Mon Mar 19 22:21:04 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 9508B16A402 for ; Mon, 19 Mar 2007 22:21:04 +0000 (UTC) (envelope-from kml@patheticgeek.net) Received: from patheticgeek.net (dsl092-035-004.lax1.dsl.speakeasy.net [66.92.35.4]) by mx1.freebsd.org (Postfix) with SMTP id 4739A13C458 for ; Mon, 19 Mar 2007 22:21:04 +0000 (UTC) (envelope-from kml@patheticgeek.net) Received: (qmail 21716 invoked from network); 19 Mar 2007 21:53:25 -0000 Received: from dsl092-035-004.lax1.dsl.speakeasy.net (HELO yakko.patheticgeek.net) (66.92.35.4) by dsl092-035-004.lax1.dsl.speakeasy.net with SMTP; 19 Mar 2007 21:53:25 -0000 Date: Mon, 19 Mar 2007 14:54:22 -0700 From: Kevin Lahey To: freebsd-net@freebsd.org Message-ID: <20070319145422.39bfddcd@yakko.patheticgeek.net> In-Reply-To: <994cd1cf0703052105y375679a4t482f4e35988f9daf@mail.gmail.com> References: <994cd1cf0703050842r5e54daa6y5fe6af3083e15cd@mail.gmail.com> <45EC6E88.3080101@tomjudge.com> <20070305115615.W38684@orthanc.ca> <994cd1cf0703052105y375679a4t482f4e35988f9daf@mail.gmail.com> X-Mailer: Sylpheed-Claws 2.5.5 (GTK+ 2.10.6; i386--netbsdelf) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: PMTU Discovery support X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Mar 2007 22:21:04 -0000 On Tue, 6 Mar 2007 10:35:42 +0530 "aditya kiran" wrote: > RFC 1191 says to increase the PMTU at some itnerval (15 minutes default) 10 minutes. > next time a packet is sent, this will be used... and if PMTU is really > increased, > no ICMP error will be recieved. that shows an increase in the PMTU. I'm > trying to > understand if this mechanism is there in freebsd. any on this is appreicated It looks to me as though FreeBSD stores per-host MTU data in the hostcache, which gets purged after five minutes of inactivity. If that's actually how it works, then, yes, FreeBSD should indeed periodically probe for larger PMTUs. Of course, the real test is to set up a few hosts and see what happens, rather than speculating based on a quick perusal of the code. :-) Kevin kml@patheticgeek.net