I have several domains and a) want to check them all from 1 account and b) want to be able to write from them using that one account.
This isn’t tough w/ web clients (I use Yahoo!) but for my iOS devices it has the added challenge that I want to use the native client. That way if an app kicks me to the email UI, I can carry on as usual.
So the other emails are just forwards to my Yahoo account. No problem. But to have them as options to write from is different.
My specific issue was that I needed to specify both the incoming and outgoing servers (listed here) INCLUDING username and passwords.
From what I can tell, if you specify the incoming and outgoing servers w/ login credentials, iOS Mail will let you specify any from address you want. But if you select a service (Gmail, Yahoo, etc.) it will force you to use your specified email address across the board.