From owner-freebsd-net@FreeBSD.ORG  Tue Mar  6 05:05:46 2007
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
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 84A6A16A403
	for <freebsd-net@freebsd.org>; Tue,  6 Mar 2007 05:05:46 +0000 (UTC)
	(envelope-from adityaa.kiran@gmail.com)
Received: from wr-out-0506.google.com (wr-out-0506.google.com [64.233.184.228])
	by mx1.freebsd.org (Postfix) with ESMTP id 4160813C47E
	for <freebsd-net@freebsd.org>; Tue,  6 Mar 2007 05:05:46 +0000 (UTC)
	(envelope-from adityaa.kiran@gmail.com)
Received: by wr-out-0506.google.com with SMTP id 55so2679415wri
	for <freebsd-net@freebsd.org>; Mon, 05 Mar 2007 21:05:45 -0800 (PST)
DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta;
	h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references;
	b=JHL3qx/gxNfb4zdI/vi5yVyw+8BjIrhTpLHqLaKOG10Batug8vOURSgAHJvSJRexUWmpBlrW6W+h79hIBn/aY7XFJluwB5Sv7cK365e2VIthKAXMMtdl7Mz3T5cmnjHgry0IPEFacNPph71g9FshfZ0yYSmnBboSXr0Nx1gAe1E=
DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta;
	h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references;
	b=aTF8GcTuR6VTjOS0OietWSHMkkH/L0Xwg70UVFcfINK7O7jmCx+fmWn80OTj0VRRpR0Y27x12eHaVZoIKwtgs0vr6udVDsOK0PsyDdqxhLcVEmIglMAX61o+9jtXqDvlly7G/M9yfRAD1alF3uznPnPgDJ5oVMZI9n+DiagnUxY=
Received: by 10.114.155.1 with SMTP id c1mr1584382wae.1173157542199;
	Mon, 05 Mar 2007 21:05:42 -0800 (PST)
Received: by 10.114.145.9 with HTTP; Mon, 5 Mar 2007 21:05:42 -0800 (PST)
Message-ID: <994cd1cf0703052105y375679a4t482f4e35988f9daf@mail.gmail.com>
Date: Tue, 6 Mar 2007 10:35:42 +0530
From: "aditya kiran" <adityaa.kiran@gmail.com>
To: "Lyndon Nerenberg" <lyndon@orthanc.ca>
In-Reply-To: <20070305115615.W38684@orthanc.ca>
MIME-Version: 1.0
References: <994cd1cf0703050842r5e54daa6y5fe6af3083e15cd@mail.gmail.com>
	<45EC6E88.3080101@tomjudge.com> <20070305115615.W38684@orthanc.ca>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
X-Content-Filtered-By: Mailman/MimeDel 2.1.5
Cc: Tom Judge <tom@tomjudge.com>, freebsd-net@freebsd.org
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 <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 06 Mar 2007 05:05:46 -0000

RFC 1191 says to increase the PMTU at some itnerval (15 minutes default)
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
thanks,
Aditya


On 3/6/07, Lyndon Nerenberg <lyndon@orthanc.ca> wrote:
>
> > As I understand it, it is not possible to detect upward changes in the
> path
> > MTU as there is no mechanism for a router to generate an error when a
> packet
> > is small enough to be accommodated by the MTU of the link to the next
> hop.  I
> > may be wrong though.
>
> RFC1191 section 6.3.
>
> http://www.ietf.org/rfc/rfc1191.txt
>
> --lyndon
>