I'm looking for someone to confirm the difference between NIS and LDAP when it comes to user authentication.

I was under the impression that LDAP could be used for user authentication in the traditional sense (as in user/pw stored in a central location) similar to NIS; sort of a competing standard, if you will. After some research, I think I had the wrong impression. LDAP can be used for "user authentication" essentially by creating a list of users that are allowed to use a specific application. In other words, if a user requests to run an application, the application would query an LDAP server, and if the user ID is not in the list of approved users, then it simply refuses to run. That's not quite the user authentication I was hoping for.

So, is that an accurate picture? Or is it possible to use LDAP for login-based authentication? If so, any links to documentation?

Interesting links (see "LDAP Naming Services Compared to Other Naming Services" section):

http://docsun.cites.uiuc.edu/sun_doc...SADV5/p50.html

Thanks for the link gabriele. I looked over it, but it didn't quite clear up everything. The chart they provide does a little compare-and-contrast between NIS and LDAP, but never explicitly mentions whether LDAP can be used for user authentication. The reason I was still hesitant is because they also included DNS in the chart, and I'm fairly positive (though not 100% positive) that DNS can't be used for authentication.

After some more poking and prodding on my own, I hit pay-dirt.
LDAP Authentication for Linux

That page gives instructions to set up an LDAP server to provide user authentication. Since it requires installing libnss-ldap and pam-ldap, I get the idea that user authentication was a concept LDAP wasn't necessarily created for, but sort of shoe-horned into it. Anybody stumbling onto this thread that wants to know where to get the stuff mentioned in the article linked:
Padl open source software - pam-ldap, nss-ldap, and other pieces of software

Here's another site that looks to explain how to configure a system for LDAP authentication.
Authenticating with LDAP

Note: I have not actually put either of these instructions into practice (yet). So I cannot vouch for them.

I have been using LDAP for user authentication for approximately a year in a samba domain structure emulating a Windows domain
5 geographically distributed Samba file servers with a centralized LDAP structure.

Ldap then is also utilzed for email and potentially linux logins ( i don't have that functionality turned on in nss_switch ) to prevent users from sitting at the server consoles or attempting to connect to the server.

There is a good whitepaper on using it with Samba
http://www.idealx.org/prj/samba/smbldap-howto.en.html

This can be used to configure user authentication as well for logins