Exchange hybrid ports

fsdg 986 Reputation points

Current environment:
Exchange 2016 DAG(2 NOD) and 3rd party anti-spam in DMZ.
We need to configure hybrid and migrate couple of mailboxes to O365.
I can see that 3rd party anti-spam is not supported between Office 365 and Exchange on-premises in hybrid deployment.
„Don’t put it between Office 365 and Exchange on-premises in hybrid deployment, because the mail flow between them in hybrid deployment is considered as internal, this configuration will cause mail flow issue. Microsoft does not support any third-party SMTP gateways between EOP and the on-premises hybrid connectors; the only supported device is an Exchange Edge Transport server.“

So,I need to open ports from domain Exchange directly to O365 addreses(is this secure?)
and than configure hybrid?

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,394 questions
Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
1,918 questions
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Accepted answer
  1. Andy David - MVP 142.8K Reputation points MVP

    Correct ( or use an Exchange Edge role)
    Its only open to Exchange Online IPs and secured with certificates. Many tens of thousands have done it, I think its secure, yes :)

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  1. KyleXu-MSFT 26,211 Reputation points


    As AndyDavid said, use Edge server to replace the existing anti-spam tools, only open needed ports.

    For mail flow security, you could point MX record to Exchange online and use EOP to filter emails for your organization.

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