XFOR: Dirsync Role/Number of Servers can Change DXA Addresses (150828)

SUMMARY

The Microsoft Exchange Directory Synchronization agent (DXA) can have different email addresses depending on how many instances of the service exist in a single site and the role it plays in directory synchronization. This is allowable by the Microsoft Mail directory synchronization protocol.

MORE INFORMATION

When you install the first MSMail Connector component in a site, the DXA is assigned the MSMail alias $SYSTEM. For example:

   First server:  <organization>/<site>/$SYSTEM

When you add additional MSMail Connectors to the site, $SYSTEM is replaced by SYSTEMx, where x starts with 1 and is incremented by 1 with each additional MSMail connector installed. For example:

   Second Server: <organization>/<site>/SYSTEM1
   Third Server:  <organization>/<site>/SYSTEM2

However, if Microsoft Exchange Server is a directory synchronization requestor, the SYSTEMx address will be used, even if this is the first Microsoft Exchange Server in the site. This is because we don't know if there will be another Microsoft Exchange Server in the site that will act as a directory synchronization server, in which case the address must be $SYSTEM.

If a Microsoft Exchange Server that acts as a directory synchronization server is later changed to be a directory synchronization requestor, the DXA address will be modified to SYSTEM1. If a SYSTEM1 address already exists in the same site, SYSTEM2 will be used and so forth.