You can use the X.400 Connector to establish an X.400 messaging route between two Microsoft Exchange Server sites or between a Microsoft Exchange Server site and a foreign X.400 system. An X.400 messaging route defines the path that an X.400 message follows to reach its destination. It allows the message transfer agents (MTAs) in both sites or systems to communicate. A foreign X.400 system is a messaging system other than Microsoft Exchange Server that complies with the 1984 or 1988 X.400 standards.