Oulook access across trusted domains

We have 2 Trusted Forests each with an Exchange 2003 Organization.  They are connected with a 2 way VPN tunnel and DNS is configured for both sides.  Is there a way for a user in one forest to view the Mailbox of a user in the other forest using outlook?

I would like to have my Mailbox opened in Outlook and also add a Mailbox for a user in the other Forest.
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Not sure if you could access the entire mailbox by adding it to your Outlook profile, however you could be delegated rights and then access either calendar or inbox etc.

From the description, I understand that you want a user in domain B to access mailbox in domain A.

Since there's already a trust established, you can follow the steps
below to achieve it. I assume that you want User1 to have delegate access to User2. User2 resides in domain B2:

1) Create Associated External Account

* Create a mailbox-enabled account in domain B2 and disable this new account. We call this new account as User3.
* On the View menu, click to select Advanced Features.
* Right-click User3, and then click Properties.
* Click the Security tab, and then click Add.
* Change "From this location" to your trust domain, type in User1 and click Ok.
* In the User Properties dialog box, click User1, in the Permissions list, click
to select the Allow check box next to the Send As permission.
* Click the Exchange Advanced tab, and then click Mailbox Rights.
* Click Add, change "From this location" to your trust domain, type in
User1 and click Ok
* In the Permissions list, click to select the Allow check boxes next to
Read Permissions, Full Mailbox Access, and Associated External Account.
* Click OK.

2) Grant User3 delegate access

* Create an Outlook profile for User2, click Tools and click Options
* Click the Delegate tab and click the Add button
* Select User3 from the GAL and click Ok
* Select the desired rights for each folder and click OK
* Click Ok to quit the wizard

Hope this helps


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