I have forest trust established between forest A and B. Exchange is installed in forest A. My query is that my users in forest B will login to their computers joined to forest B with their forest B credentials. They have mailbox created in forest A and login to outlook using  forest A credentials. Will outlook connect internally or externally or not connect at all.

I know this is a little twisted and I also know about linked mailbox but I want to know how outlook would work in situation described by me above.

• Edited by pfgcgaurav Monday, July 13, 2015 8:28 PM

Hi,

You should be able to access autodiscoverer.forestA.com url from clients and ports 443,389 etc. are open.

Read this:

Configuration tips and common troubleshooting steps for multiple forest deployment of Autodiscover service:

http://blogs.technet.com/b/exchange/archive/2008/02/13/3404883.aspx

Hi Ed,

 My case is not of resource and account forest. My user has 2 AD accounts. One in forest A(where exchange is installed) and other in forest B. User is sitting in forest B and his computer is joined to forest B. User will login to computer using credentials of forest B. My requirement is user has to configure and use outlook using credentials of forest A.

 Hi Jim,

My case is not of resource and account forest. My user has 2 AD accounts. One in forest A(where exchange is installed) and other in forest B. User is sitting in forest B and his computer is joined to forest B. User will login to computer using credentials of forest B. My requirement is user has to configure and use outlook using credentials of forest A.

Hi Satyajit,

My case is not of resource and account forest. My user has 2 AD accounts. One in forest A(where exchange is installed) and other in forest B. User is sitting in forest B and his computer is joined to forest B. User will login to computer using credentials of forest B. My requirement is user has to configure and use outlook using credentials of forest A.

Does Forest B have Exchange?  If not, everything should just work just like if the user was using a non-domain-joined computer.  If it does, Autodiscover might get in the way and I'm not sure how to get around it.  In either case, you'll have to generate the profile using "Manual Setup", and you'll have to configure Outlook to prompt for a user name and password, which the user, of course, will have to enter.

Hi pfgcgaurav,

If that the case, as Ed mentioned you don't need to have a linked mailbox or the AD trust. As I said earlier your autodiscover using DNS should be working and ports for Outlook connection open. Your domainnames of forest A should be resolvable.