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Stewart9's avatar
Stewart9
Brass Contributor
Nov 23, 2019

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 ...
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oliwer_sundgren's avatar
oliwer_sundgren
Iron Contributor
Nov 25, 2019

HelloStewart9 ! 

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

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