The domain functions as the main administrative unit for your GroupWise system. Each GroupWise system has one primary domain, which was created when you first installed GroupWise. All other domains that you add are secondary domains.
The domain serves as a logical grouping of one or more post offices and is used for addressing and routing messages. Each GroupWise user has a GroupWise address that consists of a user ID, the user's post office name, the GroupWise domain name, and, optionally, an Internet domain name.
The following diagram illustrates the logical organization of a GroupWise system with multiple domains and post offices. All of the objects under the domain belong to that domain. All of the objects under a post office belong to that post office.
Messages are moved from user to user through your GroupWise system by the GroupWise agents. As illustrated above, each domain must have a Message Transfer Agent (MTA) running for it. The MTA transfers messages between domains and between post offices in the same domain. Each post office must have at least one Post Office Agent (POA) running for it. The POA delivers messages to users' mailboxes and performs a variety of post office and mailbox maintenance activities.
When you add a new domain to your GroupWise system, links define how messages are routed from one domain to another. When you add the first secondary domain, the links between the primary and secondary domains are very simple. As the number of domains grows, the links among them can become quite complex. Links are discussed in detail in Managing the Links between Domains and Post Offices.
Physically, a domain consists of a set of directories that house all the information stored in the domain. To view the structure of a domain directory, see "Domain Directory" in GroupWise 6.5 Troubleshooting 3: Message Flow and Directory Structure. The domain directory does not contain mailboxes or messages, but it does contain other vital information. For an overview, see Information Stored in the Domain. Domain directories can be located on NetWare, Linux, and Windows servers.