Exchange 2010 - Enabling Autodiscovery on cross domain

If you have a domain A with relative Exchange server and you have another B that is in bidirectional trust here they are steps that you need to follow to enable autodiscovery on users that are in B domain:

a.) On domain B you need to create DNS Pin point zones (please see this article)


  1. Primary and store in AD
  2. AD Zone replication scope:; To all DNS servers running on domain controllers in this domain (option 2)
  3. autodiscover.EmailfordomainB.XXX
  4. Do not allow dynamic updates
  5. New host A that point DAG ip/Exchange server Domain A.

b.) On Domain B you need to change "servicebindinginformation" utilizing ADSI edit (

c.) on users on domain B in AD you need to manually add email address.

d.) on workstation in domain B you need to add both domain suffixes and DNS pointing to domain B.

e.) on Domain B and DNS zones New host A named autodiscover that point DAG ip/Exchange server Domain A.

About troubleshooting you can review this interesting article: