Something very strange is happening with ldap accounts. When I try to send mail, using our smtp with tls server, sometimes the password is accepted and other times it is not. I’m going to have to do a bit of searching to find out why this doesn’t always work.
The first time I tried this, I ran authconfig on the machine running the ldap server and set it to use ldap, use ldap authentication and use tls. With these settings, I was not able to send mail through our smtp+tls server. I would just be repeatedly prompted for the password.
Later, after I used authconfig, to turn off the ldap stuff. I was able to send email using one of my ldap accounts. The only other thing I remember changing was /etc/nsswitch.conf. Where I added ldap to the passwd, shadow and group lines.
I obviously still don’t completely understand how ldap works.