External mailserver

We are working on finalising our new servers. And would like to move the mail to a dedikated server.

Now, we could just setup the mailserver on a separate machine, but I want to let the user control the accounts from interworx. in the GUI it’s easy enough to do for the MySQL, but how do we do it for the mailserver?

When the users sync in their mail from other accounts or previous provider via IMAP, the mailserver can quickly cripple the entire system. So either we move the mailservice to a separate machine, or if we could trottle the mailservers resources somehow. We will be running ASL, CloudLinux (LVE + CageFS) and Interworx on the new servers.