hoping this isn't too simplistic, but have you tried samba? I haven't yet jumped up to RH9, but I know RH 7.2 & 8 give you the option of installing samba services in the initial install. however, an even better idea no matter what version Linux you're on is to go to samba.org and grab the latest code or binaries. if you;re not familiar with samba, check out the documentation there. samba in a nutshell tho is an effective and flexible way of allowing your Linux/UNIX (and even macs) machines to be a part of a windows domain. there are many options for configuring if you want to be elaborate, but it also is extremely simple to just get your UNIX/Linux and windows machines talking with minimal config'ing.
good luck!