Date: Tue, 26 Jun 2001 08:58:04 +0300 From: Peter Pentchev <roam@orbitel.bg> To: alexus <ml@db.nexgen.com> Cc: Simon Rakovec <simon@inforta.com>, freebsd-security@freebsd.org Subject: Re: disable traceroute to my host Message-ID: <20010626085804.E780@ringworld.oblivion.bg> In-Reply-To: <01ec01c0fdb1$6c9cada0$9865fea9@book>; from ml@db.nexgen.com on Mon, Jun 25, 2001 at 04:00:03PM -0400 References: <006a01c0fb6b$2d64d830$9865fea9@book> <3B36267B.5B5FDBE@inforta.com> <20010625093731.A934@ringworld.oblivion.bg> <01ec01c0fdb1$6c9cada0$9865fea9@book>
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On Mon, Jun 25, 2001 at 04:00:03PM -0400, alexus wrote: > i agree this is not a solution.. looks like tty=1 is best solution so far TTL=1 is not a general solution, because it only blocks traceroutes to this particular host, not to any machines that it is acting as a gateway for. Moreover, TTL=1 is not a real-world solution, because some *legitimate* packets might arrive with TTL=1 (yes, there are some OS's that set too low TTL's on outgoing packets, and there are some global backbone ISP's which have a *lot* of routers, so it is possible that a normal packet destined for your host should reach you with TTL=1). And just btw.. Really, why do you want to block traceroutes? G'luck, Peter -- because I didn't think of a good beginning of it. > ----- Original Message ----- > From: "Peter Pentchev" <roam@orbitel.bg> > To: "Simon Rakovec" <simon@inforta.com> > Cc: <freebsd-security@freebsd.org> > Sent: Monday, June 25, 2001 2:37 AM > Subject: Re: disable traceroute to my host > > > > On Sun, Jun 24, 2001 at 07:42:19PM +0200, Simon Rakovec wrote: > > > Try this: > > > > > > ipfw add deny udp from any 32769-65535 to <your-host> 33434-33523 > > > > As Karsten noted in a followup, this is not proper network practice. > > There might be a LOT of things listening on those UDP ports, including > > ephemeral outgoing UDP connections. > > > > As many other people noted, this does not stop Windows traceroute, > > which goes via ICMP. > > > > As the traceroute(8) manpage notes, this does not stop people who > > know how to use the traceroute '-p port' option to select a starting > > port != 32768. > > > > As Dag-Erling Smoerdgrav noted, in general it is impossible to disable > > a person determined to traceroute you, and in practice, there is > > no need to. > > > > G'luck, > > Peter > > > > PS. How was that now... one source: plagiarism, two sources: comparative > > study, three sources: an academic thesis.. I did even better than that! > ;) > > > > -- > > Thit sentence is not self-referential because "thit" is not a word. > > > > > alexus wrote: > > > > > > > > is it possible to disable using ipfw so people won't be able to > traceroute > > > > me? To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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