From owner-freebsd-hackers Fri Jan 4 16:38: 7 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from jim.go2net.com (jim.infospace.com [206.29.197.27]) by hub.freebsd.org (Postfix) with SMTP id D7DB137B405 for ; Fri, 4 Jan 2002 16:38:00 -0800 (PST) Received: (qmail 4269 invoked from network); 5 Jan 2002 00:03:16 -0000 Received: from unknown (HELO ketel.go2net.com) (206.29.197.197) by jim.infospace.com with SMTP; 5 Jan 2002 00:03:16 -0000 Received: (qmail 4375 invoked from network); 5 Jan 2002 00:03:16 -0000 Received: from rolf.inspinc.ad ([10.99.33.65]) (envelope-sender ) by ketel.inspinc.ad (qmail-ldap-1.03) with SMTP for ; 5 Jan 2002 00:03:16 -0000 Date: Fri, 4 Jan 2002 16:03:35 -0800 Subject: Re: path_mtu_discovery Content-Type: text/plain; charset=ISO-8859-1; format=flowed Mime-Version: 1.0 (Apple Message framework v480) Cc: Terry Lambert , freebsd-hackers@FreeBSD.ORG To: Leo Bicknell From: William Carrel In-Reply-To: <20020104235622.GA53844@ussenterprise.ufp.org> Message-Id: Content-Transfer-Encoding: quoted-printable X-Mailer: Apple Mail (2.480) Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Friday, January 4, 2002, at 03:56 PM, Leo Bicknell wrote: > In a message written on Fri, Jan 04, 2002 at 01:26:54PM -0800, William=20= > Carrel wrote: >> See now you've made me curious, and I ask myself questions like: How >> robust is PMTU-D against someone malicious who wants to make us send >> tinygrams? Could the connection eventually be forced down to an MTU = so >> low that no actual data transfer could occur, or TCP frames with only >> one byte of information? > > I don't have the RFC handy, but aren't all Internet connected hosts > required to support a minimum MTU of 576 from end to end with no > fragmentation? Thus if we ever got an MTU less than 576 we should > ignore it. Right? RFC 879 (http://www.rfc.net/rfc879.html) would tend to disagree... (10) Gateways must be prepared to fragment datagrams to fit into the=20 packets of the next network, even if it smaller than 576 octets. -- Andy Carrel - william.carrel@infospace.com - +1 (425) 201-8745 Se=F1or Systems Eng. - Corporate Infrastructure Applications - InfoSpace To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message