My DHCP server (on Server NT 4.0, service pack 6a) has suddenly stopped
issueing tcp numbers.

Server is networking fine, and also functions as our Proxy server, and
filter server.

We have removed the filtering software, replaced network card, and pinged
all over the place.

Event viewer says another workstation has conflicting tcp number (number
reserved for our server), but if you shut down the server, and ping the
number in question, there is no response.

And if you ping  -a xx.xx.xx.xx  the server number,  it replys with the
server name.