Author: Patrick McHardy <kaber@trash.net>
Status: Submitted for kernel inclusion at 2.4.21-pre3 time

ipt_REJECT sends unreachables in response to UDP packets with invalid
checksums, thereby exposing the
existance of a firewall  (as described in phrack #60, "broken crc
firewall spotting" (or something like this), www.phrack.com).

The patch makes ipt_REJECT verify UDP checksums if set.                         
