On the one hand, we have the role of Mailbox Server, which has the mailbox databases and also has the Client Access part, so the access services are published (HTTPS, POP, IMAP, ActiveSync, EWS ) for users both internally and externally. The other role is Perimeter Transport, which is used for incoming SMTP emails from outside, as well as improved Antispam and Malware control functions.

As you can guess, we cannot establish the external access server in the DMZ, as we will be exposing our mailboxes to possible direct attacks.

Exchange Server system requirements

Before you install Exchange Server 2019, we recommend that you review this topic to ensure your network, hardware, software, clients, and other elements meet the requirements for Exchange 2019. Also, make sure you understand the coexistence scenarios that are supported for Exchange 2019 and earlier versions of Exchange.