One of the first issues faced by any admin who wants to convert from a MS network to Linux is authentication. In the MS world, there are NT4 domains, and the more recent Win2K Active Directory domain, which provide a central authentication db for all activities on the network. If I understand correctly, the most similar thing in the nix world is the NIS domain. But there is also the possibility of setting up an LDAP server for authentication. Let me throw out my comments and questions, and please comment and/or correct me: 1) there are no other realistic options besides the above 2 for centralized authentication for users 2) LDAP is preferable to NIS, because it offers everything NIS does, as well as (from http://diradmin.open-it.org/index.php): * Like NIS, a single source of sign-on: using LDAP, eliminating different sources and making user administration much easier. LDAP integrates with the PAM security architecture and many servers such as Apache. * Mail accounts without system accounts: you can create user accounts for several mail servers without necessarily creating a system account for them. * Centralized preference storage: you may want to centralize preferences for different applications. For example, Netscape preferences, bookmarks etc can be stored in LDAP. * Corporate address book: most e-mail software allows you to use LDAP directory servers as address book sources, so you keep your company members' information there. You can also link your directory to specialized software such as trouble tracking, and make your users log in to the software. 3) both NIS and LDAP can use encrypted & public/private key authentication techniques, including kerberos, so no passwords need to traverse the network in clear text. How does all this sound? Scott (was "boyhowdy") __________________________________________________ Do you Yahoo!? Faith Hill - Exclusive Performances, Videos & More http://faith.yahoo.com