I have a dedicated server with one root domain. There are no email accounts attached to the root domain.
Three of my sub-domains have unique IP's. Each of these three sub-domains has administrative user names that could have corresponding email address but likewise I choose not to get married to an address that I cannot easily dump. Instead, I use dozens of specific aliases and no default mail drop. Collecting email is done by logging into the POP3 server as one of the three user names and collecting email for all aliases under that account. Each account has one or two aliases that I use primarily for that account. The rest are specific to web site account registrations and spam bait.
The other dozen or so sub-domains I manage share a fourth IP, all managed similarly to the other three sub-domains.
However, the server root domain is the same for all other sub-domains.
When I added the first sub-domain primary alias, mailhosts came up with a much larger list of hosts than I expected, mostly cannonical variations of the root domain and a couple of other domains.
When I added a primary alias for the second sub-domain, the mailhost list was exactly the same.
My question therefore is which is correct:
* That I need enter only one alias for all other accounts on the server? or
* That I must enter at least one alias for each sub-domain? or
* That I must I enter all aliases for each sub-domain?