Having domain email addresses outside of Office 365


If a very small company has Office 365 Business Essentials in-place for few key people, and they want to have additional users using the same domain.com email without an O365 subscription (and maybe use the original web host non-exchange pop/imap email?), what would be the setup process?

What I've read seems to be for a pilot, and have users forward email from the original web host email account to a new O365 email address.

Can anyone suggest a document that may provide specific setup details for this?  Assuming it can be accomplished. 


4 Replies
If you mean e-mail address from the Office 365 domain without a license, your only option really is a Shared Mailbox (Via exchange admin) and then you can set the forwarding on that mailbox to the other domain.

You used to be able to use a contact to do the forwarding but I don't think you can do that without a hybrid configuration.

Hello@Stewart9 ! 

If I understand you correctly your current setup is the following 

  • 1 IMAP mail system in place ( the Active system ) 
  • 1 Office365 tenant with Exchnage Online that is being piloted 
  • 1 Custom domain 

And you want to enable both the Office365 tenant and your current Email ( IMAP ) system to receive and send emails? 

It is not possible on a DNS level to set up two separate MX records for the same domain. Meaning, you cant set up two separate email systems for the same domain, this will cause DNS errors 


If you are only piloting Office365 at the moment, then I suggest that you do the following


  1. Set up email contacts in your current IMAP system that points to the Office365 default email address of the users

With the above, you will keep your MX records pointed to your current IMAP system, meaning all emails will go there. And then you have forwarding set up for your pilot users that sends incomming emails to the default office365 domain ( company.onmicorosft.com ) 


Then ,when you are ready, I suggest that you migrate the data from the current IMAP system to Office365, and then redirect the DNS MX record to Office365 instead and decommision the current IMAP system 


If youre a small organization with not many users or email integrated services, this should be a pretty straight forward process 


Let me know if you need further assistance, i'd be more than happy to. 

Kind Regards
Oliwer Sjöberg

It really boils down to what features they will need access to. You can have as many unlicensed users as you want, and you can even get them access to some services without assigning a license. However if they want to send messages using O365, they will need a license.

@Vasil Michev 

To clarify a bit, My small company has two users now on O365 BE, with our domain setup in O365. So I'm not piloting. 

And I work with a few other small companies wanting to do this also if possible, so I'm the test-case.


None of the O365 account features would be needed for the emails not using O365.  They would use their existing email clients (Outlook, Win 10 Mail, etc.) to access their IMAP accounts.  


I had previously tested Forwarding from our email accounts (at our web hosting company) to both O365 account and an Outlook.com account.  With Forwarding setup for two different email accounts, a high percentage of the emails forwarded did not show up in the O365 inbox.  I'd be afraid tell a customer he can depend on all of his mail being delivered to the O365 account, and by the way, they would have to keep the mail server emptied manually, and separately.


I just thought it may be possible.