Set Service Type to specify what kind of server you will be running. E-mail Client means that people will be able to check their e-mail from Pop3 servers only and are not allowed to create accounts on your server. E-mail Server means that people are allowed to create accounts on your server.

Set Mail Type to specify what kind of external servers your users are allowed to access. Options are POP3, IMAP, POP3 & IMAP or No External Servers.

The MailServer is an option to hardcode the domain field, so uses can not enter their another domain account details. If you would like users to access external accounts for POP3/IMAP, leave this field blank.

Use SMTP Hostname if your SMTP is running on a different server from your web/@Mail server. Enter the fully qualified hostname or IP-address of your SMTP server. If SMTP is running on you localhost you can leave this option blank.

Set your Maximum Message Size to control the size of incoming and outgoing messages. This options is important as MySQL has a limit of the size of e-mail it it is able to store. Currently There is a 16 MB limit for MySQL version 3. MySQL version 4 and higher are only limited by the size of the RAM in your server. Enable Message Cache Support if you would like to have messages downloaded via POP3/IMAP/SQL to be available to the user on request. Messages will be stored in usr/local/atmail/tmp/ directory. This cache will be deleted every two hours and the messages purged.