From owner-freebsd-hackers@FreeBSD.ORG  Mon Jul  7 08:54:35 2003
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Date: Mon, 7 Jul 2003 18:02:52 +0200
From: Socketd <db@traceroute.dk>
To: Toni Andjelkovic <toni@soth.at>, hackers@freebsd.org
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Subject: Re: 5 "Advanced" networking questions
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On Mon, 7 Jul 2003 17:33:14 +0200
Toni Andjelkovic <toni@soth.at> wrote:

> On Mon, Jul 07 2003 (01:22:05 +0200), Socketd wrote:
> > 1. Reading "man blackhole" I found that net.inet.udp.blackhole=1
> > will prevent traceroute. Is this only if the host is the end target?
> > or will it simply disable sending an ICMP packet when it get's a
> > packet with ttl=1?
> 
> Look in sys/netinet/udp_usrreq.c. This flag operates on the UDP layer
> and doesn't interfere with TTLs.

Ok, anyway to prevent sending ICMP's when ttl = 0? Or do I need a
firewall?

Thank you for your reply!

br
socketd