Update

Some time has passed since I wrote this article but I am pleased to say that even more has happened that is relevant to Linux readers. Some highlights from the intervening period include:

1. Solaris 2.6 is now shipping and PAM is fully included.
2. The X/Open group absorbed PAM into their ``Single Sign On'' initiative.
3. Apache can be configured to use PAM for authentication.
4. The Common Desktop Environment has PAM support built in.
5. Red Hat now defaults to using pam_pwdb.so instead of the pam_unix_*.so modules.
6. Caldera's OpenLinux has adopted Linux-PAM as its authentication scheme.
7. Luigi Catuogno (Italy) has written a pam_tcfs.so module (which was hoped for in this article) as pam_cfs.so.
8. If you can find a reason, courtesy of David Airlie, you can even authenticate your Linux box with an NT server using the pam_smb.so module.

More modules are quietly being developed all the time. Work is still needed to complete PAM support in many applications (hence the focus of this article), but all in all, implementing PAM has turned out to be a good and useful project.