From owner-freebsd-hackers Tue Sep 19 7:36:22 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from envy.vuurwerk.nl (envy.vuurwerk.nl [194.178.232.112]) by hub.freebsd.org (Postfix) with SMTP id 3213F37B422 for ; Tue, 19 Sep 2000 07:36:20 -0700 (PDT) Received: (qmail 7122 invoked from network); 19 Sep 2000 14:36:18 -0000 Received: from kesteren.vuurwerk.nl (HELO daemon.vuurwerk.nl) (194.178.232.59) by envy.vuurwerk.nl with SMTP; 19 Sep 2000 14:36:18 -0000 Received: (nullmailer pid 5945 invoked by uid 11109); Tue, 19 Sep 2000 14:36:19 -0000 Date: Tue, 19 Sep 2000 16:36:19 +0200 From: Peter van Dijk To: freebsd-hackers@FreeBSD.ORG Subject: Re: traceroute using tcp to a port? Message-ID: <20000919163619.K5422@vuurwerk.nl> Mail-Followup-To: Peter van Dijk , freebsd-hackers@FreeBSD.ORG References: <00ac01c02218$7f91e080$0e00a8c0@neland.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <00ac01c02218$7f91e080$0e00a8c0@neland.dk>; from leifn@neland.dk on Tue, Sep 19, 2000 at 11:00:57AM +0200 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, Sep 19, 2000 at 11:00:57AM +0200, Leif Neland wrote: > If I understand correctly, traceroute works by sending pings with ttl=1, > ttl=2,ttl=3 etc and records the names of the routers where the ttl reaches > zero. > > However, an increasing number of sites believes in security by obscurity, > and blocks for pings. traceroute doesn't use pings. mtr does. > Would the same technique work for making a telnet to port 80 with ttl=1, > ttl=2 etc? traceroute currently uses UDP in a similar way, and a SYN ping (like nmap does) should be possible too, yes. The problem is that those sites hinder traceroutes by blocking certain kinds of *outgoing* ICMP traffic, and there's no way we can work around that. Greetz, Peter. -- [ircoper] petervd@vuurwerk.nl - Peter van Dijk / Hardbeat [student] Undernet:#groningen/wallops | IRCnet:/#alliance [developer] EFnet:#qmail _____________ [disbeliever - the world is backwards] (__VuurWerk__(--*- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message