MailInABox only allows emails to be SENT from authenticated users, and only the user’s email + any aliases created for them to send.
Are you trying to consolidate your emails?
if you are, might I recommend:
- A VPS provider of your choice (Be mindful of their ToS)
- Load ubuntu 14.04 + MIAB.
- Forward ALL emails from each other account, to an account on your MIAB server using:
a. gmail+username@example.com
b. hotmail+username@example.com
c. etc
The above (a,b,c) allow you to easily configure rules in the web mail client to move incoming email from each mail box into a folder of your choice. Also note: the “gmail+” is a tag, no need for more than one account just prepend “string+” to an email address hosted on MIAB to get it in that mailbox, but create a rule first to move that email to a specific folder. I hope this helps!
EG:
Your email could be john@smith.com
Forwarded GMail tag could be gmail+john@smith.com
Make a rule in roundcube to move any email with the tag “gmail” or to email "gmail+john@smith.com" to the folder in roundcube called “Gmail”