You must run an MTA for each domain. The MTA:
Routes messages between post offices in the local domain.
Routes messages between domains.
Routes messages to and from GWIAs that connect your GroupWise system to the Internet.
Controls the size of messages that can pass across links.
See Section 22.2.2, Restricting Message Size between Domains.
Updates the domain database (wpdomain.db) whenever GroupWise users, resources, post offices, or other GroupWise objects are added, modified, or deleted.
Replicates updates to all domains and post offices throughout your GroupWise system. This keeps the Address Book up-to-date for all GroupWise users.
Synchronizes GroupWise user information with LDAP directory user information.
See Section 6.1.2, Configuring User Synchronization for an LDAP Directory.
Synchronizes GroupWise object information throughout your GroupWise system as needed.
Detects and repairs invalid information in the domain database (wpdomain.db).
Provides logging and statistics about GroupWise message flow.