Hello, if I have a mail server for mail.aaa.com and mail.bbb.com and I added a new user and he will have newuser@aaa.com. Now I want to add an additional mailbox with e-mail newuser@bbb.com Do I have to create a new user from ADUC so that it creates an additional mailbox or can I go from Exchange 2010 and add mailbox directly from there ? I want also to give full permision for the newuser@bbb.com so that the new user can use both accounts to send from. Will right clicking on the mailbox and Give full permission achieve this ? Thank You

From the way it sounds, you are not hosting your own DNS. So you are using a POP3 connector to pull internet mail to your Exchange server? If that's the case, you will have to add the new user from your web control center at mail.aaa.com and mail.bbb.com. Then go to Exchange and add a new mailbox. Once the new mailbox is created, go to the newly created user mailbox properties, click on the Email Addresses tab, then add newuser@aaa.com and newuser@bbb.com. You can only choose one of them to reply from.

Not hosting dns however I am hosting Exchange server 2010 and users have Outlook connected to Exchange OST file

What exactly do you want to achieve ?Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

No it's ok now since I confirmed that I cannot add a mailbox without associating it with ADUC account and therefore the answer is no