ICMP Packets.

Darren Reed darrenr@reed.wattle.id.au
Wed, 3 Jun 1998 22:46:15 +1000 (EST)

In some email I received from tqbf@pobox.com, sie wrote:
> > 2) Is there a list of ICMP message types that are needed as opposed to
> ones that are just used for troubleshooting ( like echo, echo-reply )
> that can be blocked without problems.
> Not that I know of, but you should remember that for information gathering
> purposes, blocking ECHO REQUEST messages is a pretty futile gesture.

I'd second Perry's comments and mention that you're stopping PMTU from
working, for starters.  Whatever is sending out IP packets should be able
to get the ICMP errors which are returned for those packets.