NT 4.0 File Sharing not working

I have a situation here… I have a PC/client with dial up connection to a server (testing something). The client has Windows XP and the server is NT 4.0 with sp6. The problem is when I connect via a network connection, I can see any shares onthe server, but when I dial up I can’t see any shares. Any one know why this could be???

Any insight would be appreciated.

Thanx,

Zak