smurf amp nets

Sat Jun 13 19:02:12 UTC 1998

On Sat, Jun 13, 1998 at 09:19:13AM -0700, ken emery wrote:

==>Solaris also has this ability.  You need to use /usr/sbin/ndd utility to 
==>turn this off.  The RFC's say that responding to directed broadcast should 
==>be on (this has been hashed out here before) so the *nix vendors leave it 
==>enabled in the default config.

This is incorrect.  The RFC (1122, section 3.2.2.6), states:

---
   An ICMP Echo Request destined to an IP broadcast or IP
   multicast address MAY be silently discarded.

   DISCUSSION:
      This neutral provision results from a passionate debate
      between those who feel that ICMP Echo to a broadcast
      address provides a valuable diagnostic capability and
      those who feel that misuse of this feature can too
      easily create packet storms.
---

There is no SHOULD in there.

www.quadrunner.com/~chuegen/smurf.txt has a few OS vendors who have
either turned replies off by default or have provided an option.

/cah