Thanks to davidh, I have one of my old users and one new test user successfully configured with Posix and Samba information. Both are showing up when I do a getent passwd, but I can not log in with either SSH or Samba.
I get this in syslog as well, even though pam_mkhomedir is installed.
Zimbra server is ZCS NE on Ubuntu, server I'm trying to join to it is Debian Etch.
Sep 10 06:40:50 diablo sudo: PAM unable to dlopen(/lib/security/pam_mkhomedir)
Sep 10 06:40:50 diablo sudo: PAM [dlerror: /lib/security/pam_mkhomedir: cannot open shared object file: No such file or directory]
Sep 10 06:40:50 diablo sudo: PAM adding faulty module: /lib/security/pam_mkhomedir
edit: fixed that one. In the Wiki guide we're told to add the following to /etc/pam.d/common-session
it should be
session required pam_mkhomedir skel=/etc/skel umask=0077
session required pam_mkhomedir.so skel=/etc/skel umask=0077
edit2: after rebooting Diablo, I can now log in via SSH. Samba still didn't work for my existing users until I did a "sudo smbpasswd -a <user>" which added the proper password information to LDAP. As of right now the only thing which isn't working is the above mkhomedir functionality, it's not throwing any errors but the home directories are not being created properly.