PAM

Pluggable Authentication Modules are a set of libraries created by SUN to allow easy and secure configuration of multiple authentication libraries on UNIX. If you are running Linux or Solaris you are already running PAM. Beware that despite being created by SUN, Solaris utilities have a history of incompatability with their parent companies published PAM library protocol standards.

PAM configuration lives in either /etc/pam.conf or as seperate files in /etc/pam.d/.

Full PAM docs and lists of available modules are available here:

http://www.us.kernel.org/pub/linux/libs/pam/Linux-PAM-html/

At A.S.C. we use PAM to authenticate from a RADIUS server as the first choice before falling back to the system password file.

PAM can also allow authentication to NIS+, Samba, Windows NT, Novell NDS, and LDAP.

There are PAM authentication modules for applications like Apache as well.

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