Mar 262010

Authoritative OK. Of the approximately 6 people who have seen this site, everyone bailed about halfway through that headline except the guy I worked with who wrote this how-to. No problem, I’ll just press on. :)

So, what did that headline mean? In one of my previous articles on Exchange Hosted, I mentioned ‘email coexistence’. What this means, is that we weren’t ready to shut our Exchange server down. There were accounts on that server that either has not been migrated, or were not ready to be disabled. So what Exchange hosted allows you to do is set up your Exchange server as an External Relay.

This means that when someone mails you at, the email hits your Exchange server first, then your Exchange forwards a copy of that message to MSOL if the receiving account has already been migrated.  This creates an environment where pre-migration and post-migration clients can communicate with each other through without knowing what is happening behind the scenes.

The problems with this are obvious:

  • Email is slowed down because it has to be received, stored, and scanned by two Exchange servers.
  • You’re trying to get rid of the old Exchange server.
  • It adds complexity to your life. When you add a new user, you can’t just add them to MSOL’s user list, you need to still add them to your legacy Exchange server and set up forwarding.
  • More complexity. An email didn’t arrive. Did it reach my Exchange server? Whose spam filter trapped it?

So, you’re ready to remove your old Exchange server from the mix.  Performing these steps won’t actually decommission the server- it just stops incoming mail, and makes MSOL Exchange hosted the Authoritative email server. I recommend weighing the pros and cons of when you make the switch.

  1. Log into the Admin panel (
  2. In another tab of the Web browser, log into your domain registrar’s (or current host’s) account manager. (you will need to change MX records shortly)
  3. Click the Users tab, and then ‘View Domains’ text link to the right.
  4. You will have two entries in here (at least) and Click to edit it.
  5. Select “the ‘Authoritative’ radio button, then click ‘Save’ down in the bottom, or the change will not be saved.
  6. In the same popup window, click the ‘Inbound Messaging’ tab.
  7. Click the ‘Enabled’ button, and click ‘Save’.
  8. Jump into your Domain’s settings, and change your MX record to whatever the instructions under the “’Enable’ button ask. For us, it was I recommend pasting that right over the current MX name record if you don’t want to mess with priorities and TTL. Save your changes, and update your domain’s records. Your host should notify you it will take hours to days for the change to fully propagate.
  9. Jump back to your MSOL tab, and click ‘Finish’. It should notify you the changes were successful. We received a failure once when we skipped the Save step in step #5.

That’s it! MSOL should now receive all of’s email, and you’ll be ready to decommission that old Exchange server!


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