Exchange 2013 Hybrid. Configure Edge Transport mailflow only between onpremise and Office 365 Exchange tenant


  • Hello,

    We are in the middle of configuring our organization with Microsoft’s Azure cloud. I've set up AD Connect in combination with ADFS.

    We have 7 domains in federated mode synchronized from our on premise Active Directory and one domain in managed mode with cloud only users.

    Now i'm configuring our Exchange 2013 environment to hybrid with Exchange online. For our on premise Exchange CAS and Mailbox servers, we have a third-party smtp Gateway / spam filter solution.

    In the future we would like to migrate our mailboxes to office 365. But for now i would like to keep our on premise server as primary system. So i've chosen to route all mail through our on premise Exchange so it has to go through our third-party smtp Gateway / spam filter solution.

    The mail flow between on premise Exchange and Office 365 Exchange is not allowed  to go through our third-party smtp Gateway / spam filter solution. Because i don’t want direct access on port 25 from EOP to our Exchange server i prefer to setup an Edge Transport server in our DMZ for this.

    I do not have a lot of experience with setting up Edge Transport server. But there is a lot of good documentation on the internet about it.

    Where i get confused about (and that is where I did not find any documentation about) is how to accomplish that external inbound / outbound e-mail use the third-party smtp Gateway / spam filter except the mail flow between our Exchange 2013 on premise <-------> Exchange 2013 Office 365 tenant . Standard Edge Transport deployment configures all external e-mail to go through the Edge Transport Server.

    Any advice about this design would be greatly appreciated.

    Tuesday, June 6, 2017 3:23 PM


  • Hi,

    You can refer to the following screenshot, you need to create a send connector to route mails to getaway and a receive connector for this gateway:

    Hope it helps.


    Jason Chao

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    Wednesday, June 7, 2017 6:37 AM