FreeBSD NIS server authenticating Linux

[Enrique Ayesta Perojo]

Hello, i'm trying to bind a Linux client (Fedora Core 5) to a FreeBSD 6.1-RC 
NIS Server. The linux client seems to bind correctly to the NIS Domain. 
Anyway when i try to log into the linux machine i can't log in. As i have 
seen on google, there seems to be some kind of problem with a neccesary 
shadow map for the linux machine to authenticate, but these seems to be old 
problems.

Any ideas on what is happening really and some way to solve it?

Thanks a lot