Mark's questions

My goal is to configure DNS servers on the client side.
I was following the guide at: https://help.ubuntu.com/lts/serverguide/network-configuration.html#name-resolution.
My /etc/network/interfaces looks nothing like the example in the guide.
When I cat /etc/network/interfaces, I get:
# interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback
and nothing else...

• I installed and configured a test server with OpenLDAP and created a user with username (uid) "jdoe", following some of the guide at: https://help.ubuntu.com/lts/serverguide/openldap-server.html.
• I used phpLDAPadmin to create my OUs and users.
• I installed and configured libnss-ldap per the guide.
• I can su - jdoe and it works okay.
• I configured /etc/lightdm/lightdm.conf to show a manual login.
• I could log in to Ubuntu graphically (with the LightDM greeter) as "jdoe", until changing jdoe's uid to 5000. I changed this because I noticed his and my uids were both set to 1000, which I think caused some weird issues. Now, when I try logging in graphically as jdoe, I get a sound and the screen flashes, but it does not log jdoe in to his Ubuntu desktop. I noticed when I create a new user in phpLDAPadmin, their uid defaults to 1000 - the same as my uid... Is this how it's supposed to work?

I have installed OpenLDAP, and configured some basic users. Next, I want to configure users in my directory to be able to authenticate through my server. I was reading a little about something called PAM. Is this what I should use? If so, can someone point me to some good instructions?

I'm in the process of installing OpenLDAP, and the README file states that "Reentrant POSIX REGEX software" is required. Is there a package I can install with apt install to get this?