Exchange 2013 SP1 – MAPI over HTTP

In my previous post I talked about creating a DAG without an AAP.

In this post I want to talk about another new feature in Exchange 2013 Sp1 know as MAPI over HTTP.

All Previous version of Exchange communicated with outlook clients using the RPC Protocol. Since Exchange 2003 there has been a second protocol available to connect to the server –  RPC over http also know as outlook anywhere. This option was mainly used for secure external access (Outlook clients that are outside of the exchange network) to the Exchange server.
Exchange 2013 used this protocol (Outlook Anywhere) for all communications both internal and external.

Now with SP1 a new communication protocol has been added – MAPI over HTTP.
The benefits of using MAPI over HTTP are:

  • Provides faster reconnection times after a communications break because only TCP connections—not RPC connections—need to be rebuilt. Examples of a communication break include:
    • Device hibernation
    • Changing from a wired network to a wireless or cellular network
  • Offers a session context that is not dependent on the connection. The server maintains the session context for a configurable period of time—even if the user changes networks.

First thing to mention is that MAPI over HTTP is only supported for outlook 2013 Sp1 clients. All previous clients will continue to use RPC over HTTP/Outlook Anywhere.
The second thing is that MAPI over HTTP is not enabled by default.

To enable MAPI over HTTP you need to complete the following steps:

1. Virtual directory configuration – By default, Exchange 2013 SP1 creates a virtual directory for MAPI over HTTP. You use the Set-MapiVirtualDirectory cmdlet to configure the virtual directory. You must configure an internal URL, an external URL, or both.

For example, to configure the default MAPI virtual directory on the local Exchange server by setting the internal URL value to, and the authentication method to Negotiate, run the following command:

Set-MapiVirtualDirectory -Identity "Contoso\mapi (Default Web Site)" -InternalUrl -IISAuthenticationMethods Negotiate

2. Certificate configuration – The digital certificate used by your Exchange environment must include the same InternalURL and ExternalURL values that are defined on the MAPI virtual directory.  As always make sure the Exchange certificate is trusted on the Outlook client workstation and that there are no certificate errors, especially when you access the URLs configured on the MAPI virtual directory.

3. Update server rules – Verify that your load balancers, reverse proxies, and firewalls are configured to allow access to the MAPI over HTTP virtual directory.

4. Enable MAPI over HTTP in your Exchange Organization -Run the following command:

Set-OrganizationConfig -MapiHttpEnabled $true

Caution: Do not enable Mapi Overt Http if you are still migrating from Exchange 2007/2010. 
Doing so may cause outlook 2013 SP1 client to lose connectivity to public folders.

One thought on “Exchange 2013 SP1 – MAPI over HTTP

  1. Pingback: Exchange 2013 SP1 – MAPI over HTTP – Online News Portal

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