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)

autodiscover.EmailfordomainB.XXX

webmail.OWANAMEfromdomainA.xxx 

http://www.msexchange.org/articles-tutorials/exchange-server-2010/mobility-client-access/using-pinpoint-dns-zones-exchange-2010.html 

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 (https://theucguy.net/service-connection-point-scp-in/)

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:

http://www.msexchange.org/articles-tutorials/exchange-server-2010/management-administration/exchange-autodiscover.html