I use different domain addresses (ie email@example.com firstname.lastname@example.org), alias of the same exchange mailbox. DNS MX records for 'aa.com' and 'bb.com' points to the same exchange server. Receiving mails works perfect, the issue is sending mails.
How can we setup outlook and/or exchange to allow us to send mails, using a different 'from' and 'reply to' than the primary address associated with the mailbox?
By default, using just the alias on the 'From' (Outlook client) the message bounce back:
Create another server mailbox, 'forward' incoming mail to the primary and allow 'send as...', is not the answer.