After you establish links between a domain in your GroupWise system and a domain in an external GroupWise system, the MTA in your system and an MTA in the other system can route messages to the respective external systems as long as the message is addressed with a fully-qualified GroupWise address in one of the following formats:
user@internet_domain userID.post_office.domain
To simplify addressing for your GroupWise users, you can exchange information between the two systems. This enables users in your GroupWise system to use the GroupWise Address Book when selecting recipients from the other system. For information, continue with Exchanging Information Between Systems.