Service availability Hybrid Exchange

Copper Contributor

 I have a question regarding a full hybrid environment and the service availability. This is our current scenario:

We are currently moving On-Premise Exchange 2010 mailboxes to Exchange Online. The MX record is still pointing to the On-Premise environment.


The expected final scenario is the following:

  • All mailboxes should be in Exchange Online.
  • The MX record should point to Exchange Online.
  • Keep the hybrid environment due to some connectors.



  1. In this final scenario, the Autodiscover record should still be pointing to Exchange On-Premise. Is this correct or can it be changed to Online? Our understanding is that it can´t be changed so that it points to Online.
  2. In the final scenario, is there an availability problem with the service for the mailboxes in Exchange Online if the On-Premise server is not available?
    1. We understand that it won´t be possible to "create a new Outlook profile" since the autodiscover record does not respond.
    2. It´s our understanding that the connectors won´t work since the On-Premise Exchange won´t be available.
    3. Is there anything we´re missing that will stop working for the users in Exchange Online?
3 Replies

Hi Javier,


Is advised that you have a Hybrid Server in a newest version, like Exchange 2016.


In the final scenario if you does not use any Mailbox on-premises you can point the Autodiscover to Office 365.


The connectors will not work if your Exchange isn't available.

Hi Nuno thanks for your reply. If at some point in the future we have a mailbox on exchange onpremise, in addition to those already in Online. Since I am looking for a long-term exchange hybrid the question is about the availability of the mailbox that is online, is there any impact for those outlook users taking into account that the autodiscover registration points to onpremise and this server is not available?

Hi Javier,


If you have Mailboxed on-premises, you need to have the Autodiscover point to your On-premises Exchange, or you will have issues.