Access to the Internic Blocked

Vadim Antonov avg at
Fri Aug 23 01:49:39 UTC 1996

Thre reason why traceroute uses UDP instead of ICMP is
very simple -- there are a lot of broken-as-designed
unices which either do not provide non-superuser access
to harmless ICMP facilities, or cannot trace replies back
to originating process.

I'd rather fix operating systems than leaving a nice big
vulnerability in the network.


>From avg Thu Aug 22 17:36:34 1996
Subject: Re: Access to the Internic Blocked
To: Geoff Huston <gih at>
Date: 	Thu, 22 Aug 1996 01:52:45 -0400 (EDT)
From: John Hawkinson <jhawk at>
Cc: nanog at

> >On itself, LSRR is a godsend to hackers (i can think of about
> >a dozen of very nasty attacks using general LSRR).  The only
> >useful application for it is traceroute.
> >
> >Why don't router vendors provide an option to turn it
> >off for everything but ICMP ECHO?
> Personally I find this an excellent suggestion.

So now I need to hack my traceroute to send ICMP_ECHO_REQUESTS instead
of high-port udp packets?

Oh well, I guess we can put this right next to the patches to have
traceroute send TCP SYNs to get through stupid firewalls.



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