I had assumed domain alias makes mails go to the destination domain mailboxes, but I now notice mails go both to the source mailboxes and destination mailboxes. So mails are stored twice and user reads them twice. Should I have removed the mailboxess from source to prevent this? Is there a better way, when user has old domain which is being decommissioned but e-mail still arrives there, and it should be moved to customers new mailboxes on the new e-mail domain? In other words, I want no mail to go to the old mailboxes anymore.
