Couple of Questions - Hopefully basic

Ok so I’ve got my Virtualmin Pro server all setup and (seemingly) running fine.

I do seem to have a few problems and questions though.

[ol]
[li]1: When I create a new virtual server it automagically adds all the DNS entries. This in itself is pretty cool, but help me understand what the “m.domain.com” entry is used for? I can’t seem to figure out a reason for it. It creates “mail.domain.com” as well so i’m not sure wha the difference is.[/li]

[li]2: This is probably very basic, but I can’t seem to find anywhere the settings for mail clients???[/li]

[li]3: Is SquirrelMail supposed to work? When I try to go to a new virtual server "domain.com/webmail I get the following error:

[code:1]ERROR: Config file ’ . '“config/config.php” not found. You need to ’ . 'configure SquirrelMail before you can use it.
'; exit; } // If we are, go ahead to the login page. header(‘Location: src/login.php’); ?>[/code:1] Obviously I need to configure it, but I thought this was supposed to do it for me?[/li]

[li]Last Question: What is the user that VirtualMin runs on. For example, my server architecture includes an NFS mounted drive volume which is hosted on a Windows Services for Unix (Win2003) connected to an older (but still very usable) fibre channel raid array. I have to manually add the user maps and I need to know what user its using. When i try to run the backup it just fails writing to the drive.[/li]
[/ol]

Thanks for your help!

1 the m. entry is for the spam delivery as far as I am aware of.
2 in the left pane I have:
Edit Mail and FTP Users
Edit Mail Aliases
Would that be it? Select a domain in the dropdown menu for the domain you want to edit.
3 Squirrel is a script you can install under "Install scripts" in the VM professional version. Also Horde is available and phpmyadmin.
4 as far as i know it is running as root. /var/webmin