From owner-freebsd-hackers  Wed Dec 17 17:22:22 1997
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From: Andrew Gordon <arg@arg1.demon.co.uk>
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Subject: Re: ifconfig reports bogus netmask
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On Wed, 17 Dec 1997 sthaug@nethelp.no wrote:

> > This is only a problem if you want everyone to see your network topology.
> > But why would someone need to traceroute you from another AS?
> 
> - I traceroute to other ASes every day, and I find it extremely useful
> to see for instance where a path stops.
> 
> - traceroute is not the only use for ICMP.

Notably, TCP path MTU discovery - where not seeing the ICMP messages
rejecting your too-big packets can stop things working altogether.