If you have a dedicated server, that is, your own Zimbra server, it may be managed and monitored remotely by 01.com, or hosted with 01.com at one of its data centers. When you have your own server, you may have access to the most-privileged account level, the admin. The admin can control many server-wide features, here's a picture of the admin's available options for a particular user/account/mailbox, in the admin GUI. Note that 01.com systems engineers typically only use the CLI.