UNIX to NT solved

[mreiter () gwillness osd mil]

The solution - reload from a backup disk and reboot.  Apparently, a file
had been corrupted.  Thanks to all those who made suggestions.
FYI -
We had a packet sniffer on, and it confirmed that the problem was in the
UNIX box
TCPDUMP showed me that the pings were being received and recognized, but
not answered
ICMP traffic was not being filtered
We were on the trusted side of the firewall