Microsoft Exchange Server 2016 brings a new set of technologies, features, and services to Exchange Server, the messaging platform that provides email, scheduling, and tools for custom collaboration and messaging service applications. Its goal is to support people and organizations as their work habits evolve from a communication focus to a collaboration focus. At the same time, Exchange 2016 helps lower the total cost of ownership whether you deploy Exchange 2016 on-premises or provision your mailboxes in the cloud.
The Mailbox server in Exchange 2016 includes all of the server components from the Exchange 2013 Mailbox and Client Access server roles:
1- Client Access services provide authentication, limited redirection, and proxy services. Client Access services don’t do any data rendering and offer all the usual client access protocols: HTTP, POP and IMAP, and SMTP.
2- Mailbox services include all the traditional server components found in the Exchange 2013 Mailbox server role: the backend client access protocols, Transport service, Mailbox databases, and Unified Messaging. The Mailbox server handles all activity for the active mailboxes on that server.
The Edge Transport role is typically deployed in your perimeter network, outside your internal Active Directory forest, and is designed to minimize the attack surface of your Exchange deployment. By handling all Internet-facing mail flow, it also adds additional layers of message protection and security against viruses and spam, and can apply mail flow rules (also known as transport rules) to control message flow.
Outlook on the web (formerly Outlook Web App)
Outlook Web App is now known as Outlook on the web, which continues to let users access their Exchange mailbox from almost any web browser.
he former Outlook Web App user interface has been updated and optimized for tablets and smart phones, in addition to desktop and laptop computers.
MAPI over HTTP
MAPI over HTTP is now the default protocol that Outlook uses to communicate with Exchange. MAPI over HTTP improves the reliability and stability of the Outlook and Exchange connections by moving the transport layer to the industry-standard HTTP model. This allows a higher level of visibility of transport errors and enhanced recoverability. Additional functionality includes support for an explicit pause-and-resume function, which enables supported clients to change networks or resume from hibernation while maintaining the same server context.
MAPI over HTTP isn’t enabled in organizations where the following conditions are both true:
– You’re installing Exchange 2016 in an organization that already has Exchange 2013 servers installed.
– MAPI over HTTP wasn’t enabled in Exchange 2013.