Virtual Domain Administration

ISPs will appreciate virtual domain support by hostname (sharing the primary domain IP address) or by IP address (on a multi-homed server). To create a virtual domain, just use any IMail admin interface to specify the registered hostname, aliases, mailbox directory, and User Database type (right). Domain quotas can be established for mailbox size, number of messages, number of users, and maximum message size.

The next step is to create users for the new domain. To delegate user administration to the customer, simply create one user with self-management privileges: check "host administration" to grant control over users, aliases, and processing rules that affect mail for that user's entire domain. The host admin can then create additional users with Web Messaging or IMonitor and any browser. All virtual domain users log in as username@virtualhost, where virtualhost is mapped to an IP address assigned to the IMail Server.

The host admin can specify domain processing rules—filters similar to those for individual lists and users, but applied first to increase efficiency. Using rules, messages can be redirected to a selected user-mailbox, or sent to NUL (discarded). I had no trouble discarding spam or redirecting messages to a mailbox owned by the original recipient, but was unable to redirect mail intended for one user to another user's mailbox.

Virtual domains can be configured to display a "News of the Day" message after web client login. Banner ads and/or trailers can be displayed at the top and bottom of every Web Messaging page. As noted previously, even the HTML for a virtual domain's web client can be modified. These features allow a domain customer to create his own webmail client "look and feel". However, I had to restart the Web Messaging service to activate certain customizations—not something host admins are able to do by themselves.

IMail also provides a utility to add, modify, or delete virtual domains in batch mode. For example, "adddomain -h www.phifer.com -delete" eliminated my entire virtual domain (but not my existing mail directory). Adddomain allows integration with upstream systems and quick restoration of initial or archived domain settings.