CommuniGate Pro Server can serve Accounts, Goups, Mailing Lists, Forwarders and other objects in its Main Domain, and, optionally, in multiple Secondary Domains, each with its own set of Accounts (and other objects such as Mailing Lists, Groups, and Forwarders).
Every Domain can have zero, one, or several Domain Aliases (alternative names). All Domain names and Domain Aliases should be unique, and they should be registered with the Domain Name System (DNS).
In many cases, a Domain should not have a separate set of user Accounts, but should rather be a domain name alias for an already existing CommuniGate Pro Domain. You may also want to serve some domain names using account mapping and/or Unified Domain-Wide Accounts.
In all these cases, you do not have to create a new CommuniGate Pro Domain to serve a domain name.
When a client application connects to your CommuniGate Pro Server, and specifies an account name, the Server has to decide in which Domain to look for that Account. See the Access section for the details.