Date: Tue, 19 Sep 2000 16:36:19 +0200 From: Peter van Dijk <petervd@vuurwerk.nl> To: freebsd-hackers@FreeBSD.ORG Subject: Re: traceroute using tcp to a port? Message-ID: <20000919163619.K5422@vuurwerk.nl> In-Reply-To: <00ac01c02218$7f91e080$0e00a8c0@neland.dk>; from leifn@neland.dk on Tue, Sep 19, 2000 at 11:00:57AM %2B0200 References: <00ac01c02218$7f91e080$0e00a8c0@neland.dk>
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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
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