From owner-freebsd-security Thu Aug 17 9:13:58 2000 Delivered-To: freebsd-security@freebsd.org Received: from ns.yogotech.com (ns.yogotech.com [206.127.123.66]) by hub.freebsd.org (Postfix) with ESMTP id 8B2F737B72B for ; Thu, 17 Aug 2000 09:13:52 -0700 (PDT) Received: from nomad.yogotech.com (nomad.yogotech.com [206.127.123.131]) by ns.yogotech.com (8.9.3/8.9.3) with ESMTP id KAA16164; Thu, 17 Aug 2000 10:13:22 -0600 (MDT) (envelope-from nate@nomad.yogotech.com) Received: (from nate@localhost) by nomad.yogotech.com (8.8.8/8.8.8) id KAA23225; Thu, 17 Aug 2000 10:12:29 -0600 (MDT) (envelope-from nate) Date: Thu, 17 Aug 2000 10:12:29 -0600 (MDT) Message-Id: <200008171612.KAA23225@nomad.yogotech.com> From: Nate Williams MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit To: sthaug@nethelp.no Cc: dhw@whistle.com, achilov@granch.ru, Egon.Rath@lsr-ooe.gv.at, freebsd-security@FreeBSD.ORG Subject: Re: AW: deny incoming icmp In-Reply-To: <57904.966523813@verdi.nethelp.no> References: <200008171414.HAA02662@pau-amma.whistle.com> <57904.966523813@verdi.nethelp.no> X-Mailer: VM 6.34 under 19.16 "Lille" XEmacs Lucid Reply-To: nate@yogotech.com (Nate Williams) Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > > >Traceroute uses ICMP types 0 (Echo Reply), 8 (Echo request) and 11 (TTL > > >expired) to determine the route to the host. > > > > That didn't seem quite right to me, so I looked (in > > /usr/src/contrib/traceroute/traceroute.c); there is a rather large > > comment block near the beginning of the file tagged > > > > * -- Van Jacobson (van@ee.lbl.gov) > > * Tue Dec 20 03:50:13 PST 1988 > > > > that explains how & why the program uses high-numbered UDP datagrams for > > the probes. It does rely on ICMP (time exceeded; ICMP type 11) for > > receiving notification from a router, though. > > The Microsoft implementation of traceroute uses ICMP instead of UDP > though... Not as far as I can tell, since it wouldn't work with my firewall if it did. However, I haven't done any explicit testing to see what exactly it does. Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message