clients can't ping outside

I'm running BM3.9sp2 on NW6.5sp7
I have a filter defined to allow ICMP in/out both public and private NIC's
on the server.
From the server, I can ping outside addresses when I have this filter in
place, can't when I remove this filter.
However, the clients can't ping outside addresses with or without the filter
in place. In fact, if I unload ipflt and filtsrv, the clients still can't
ping outside addresses.
They get a 'destination net unreachable' error. The clients def gw points to
the BM server and the clients are on the same lan segment as the server.
Any ideas what I can try to fix this problem?
TIA