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New Exchange standard

Kicking the Tires

Article from ADMIN 36/2016

By Christian Schulenburg

Service Pack 1 for Exchange 2013 introduced a new protocol, which has become the default in Exchange 2016: MAPI over HTTP.

Exchange 2013 initially supported Remote Procedure Call (RPC) over HTTP for Outlook Anywhere as the only access protocol. Although it offered many benefits, it also put obstacles in the way of many a migration. This article introduces the new protocol, Messaging Application Programming Interface (MAPI) over HTTP and looks to facilitate the transition.

RPC over HTTP has established itself over the years as a transport protocol standard for accessing Outlook and enjoyed a good reputation, in terms of stability. However, the protocol was not intended for constant network changes, and deficits began to show, especially through the spread of Office 365. To better meet current requirements and to enable a faster connection between the client and server, a new protocol with a simpler architecture was introduced in 2014.

Background

The user experience is greatly enhanced with the MAPI over HTTP protocol. For example, the majority of clients establishes a connection within approximately 30 seconds after first launching Outlook, instead of taking 90 seconds as with Outlook Anywhere. Also, on re-establishing the connection after sleeping or changing the network, Outlook connects to the server faster than before. It supports the continuation of an interrupted connection, meaning that short interruptions no longer lead to a reconnect. The client continues the communication at the point before it broke down, if it is no longer than 15 minutes [1].

MAPI over HTTP offers several advantages not only for users, but also for administrators. The access log is no longer double wrapped. Therefore, the Internet Information Services (IIS) and HTTP proxy protocols offer far more information, much like Outlook Web Access, thus making it worthwhile to take a look at the logfiles of the various protocols. The authentication configuration has also been

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