Re: ICMP Packets.

[Bennett Todd <bet () rahul net>]

Thanks Ge' Weijers for inspiring me to actually start working on
this:-). Borrowing your excellent table format, what happens --- what,
if anything, would I break --- if I restricted ICMP to

Type    Description                     rule
------------------------------------------------------
  3     destination unreachable         allow both [1]
  *     anything else                   block

[1] I don't want to have to wait for a timeout if I try to connect to a
    site who isn't there so I want to allow in; and if someone forges
    one of my IP addresses as the source of a SYN attack, I want the
    victim to be able to get a quick notification that no, it wasn't me
    tried to set up that connection. The ``Fragmentation Needed and
    Don't Fragment was Set'' packet discussed re path MTU discovery is
    also a sub-type of this one (code 4).

I started with RFC 1700, but it looks like newer and mode detailed info
is in <URL:ftp://ftp.isi.edu/in-notes/iana/assignments/icmp-parameters>.

-Bennett