Mail resources on a mail domain that has a mail domain alias will all have alternative addresses. Mail resources and their aliases will have different domain parts (i.e. mail domain and its alias) and the same resource names. For instance, with example.net being a mail alias to example.com, every mail resource on example.com will have a counterpart on example.net, specifically:
firstname.lastname@example.org will be an alternative mail address to email@example.com
firstname.lastname@example.org will be an alternative mail address to email@example.com
firstname.lastname@example.org will be an alternative mail address to email@example.com
To create a Mail Domain Alias:
Important: When removing mail domain alias, you remove aliases for ALL your mail resources on the primary mail domain. You cannot remove a mail domain alias for an individual mail resource.
To remove a mail domain alias: