Serial connection NT4-NT2000

I’m trying to connect a NT2000pro (guest/ip) workstation to a NT4SP6 (host) workstation via a serial connection (RS232) using RAS,TCP-IP and WINS.
Problem : I can make the connection (ping, dial-up with nt2000 onto NT4SP6 Ras-server)but when usingexplorer, in network neighbourhood, both pc’s can only see themselves (and their domain, which I gave identical names).

What protocol or service is missing to do this. Is it possible ?