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shockotechcom's avatar
shockotechcom
Iron Contributor
Oct 18, 2020

Exchange Classic Hybrid Firewall Requirements

I am setting up Exchange Classic Hybrid. All mail flow will continue through our DataCentre Exchange Servers. I am unsure of exactly what needs to be allowed on my firewall. The deployment https://do...
exchange
hybrid
networking
BenKrah's avatar
BenKrah
Brass Contributor
Oct 19, 2020

Hi shockotechcom,

 

your table is correct - if all client systems (also means servers, printers, etc. sending mail via Exchange) connect to Exchange on-premises, you do not need port 587 to be open.

The connections between Exchange OP and EXO only need 443, 80 and 25. You must allow every IP range/URL that uses one or more of these ports from the list on the website you provided (https://docs.microsoft.com/en-us/microsoft-365/enterprise/urls-and-ip-address-ranges?view=o365-worldwide#skype-for-business-online-and-microsoft-teams).

  • shockotechcom's avatar
    shockotechcom
    Iron Contributor
    Oct 19, 2020

    BenKrah thanks for the reply but you indicate my table i not correct? I don't have port 80. What is that used for? 

    • BenKrah's avatar
      BenKrah
      Brass Contributor
      Oct 20, 2020

      Hi shockotechcom,

       

      never mind - port 80 is required for certificate revocation check in other scenarios but not for hybrid configuration itself.

      • shockotechcom's avatar
        shockotechcom
        Iron Contributor
        Oct 22, 2020

        BenKrah Thanks! So the hybrid connector does not do CRL check?

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