You should not use NIS, the Network Information Service, if possible, because it allows password sharing. This can be highly insecure if your setup is broken.
If you need password sharing between machines, you might want to consider using other alternatives. For example, you can setup an LDAP server and configure PAM on your system in order to contact the LDAP server for user authentication. You can find a detailed setup in the
http://www.tldp.org/HOWTO/LDAP-HOWTO.html (
/usr/share/doc/HOWTO/en-txt/LDAP-HOWTO.txt.gz).
FIXME (jfs): Add info on how to set this up in Debian.
