If you no longer want to exchange directory information with MS Mail 3.x systems, you can delete a dirsync requestor or dirsync server.
If you delete a dirsync requestor, all addresses from the dirsync requestor are removed from the Microsoft Exchange Server global address list.
You must remove all remote dirsync requestor objects from the organization hierarchy before you can remove a dirsync server. When you have removed the appropriate items, delete the custom recipient objects for each remote dirsync requestor.
Caution Do not delete a dirsync server object from a Microsoft Exchange Server organization until all active requestors have been configured to use another server. Deleting a dirsync server with active requestors can result in messaging and directory failures and possible data loss.