from an XP SP PC with NW Client 4.90 SP2...

If I ping a Windows W2K/NT server with size 2048 I get a reply.
If I ping a NW6 SP5 server with size 2048 I get no reply.

The NW server is set to accept large ping packets up to 20480 (default)

This behaviour mucks up the XP's slow link detection algorithm, which
means even though I'm on a 10Mbps connection gpresult.exe shows me as
having a slow link.

Any idea why the NW server isn't replying to 2048 byte pings?