I have a customer with an Exchange 2003 server. They had two domain names in the box (domain-1.com and domain-2.com). The company spun off the domain-2 division which is now at a different location and has their own seperate server.
I have rebuilt the address books and ensured that all references in exchange to domain-2.com have been removed.
If domain-2.com sends an email to a user at domain-1 it gets there no problem. If a user at domain-1.com emails to a user at domain-2.com it failed with a mail account does not exist at the organization.
With Veeam Explorer for Microsoft Exchange you can choose the Exchange Servers and restore points you’re interested in, and Veeam Explorer will present the contents of those mailbox stores for browsing, searching and exporting.