Exchange 2013 MAPI over HTTP(S)

MAPI over HTTP(S) Implementation Steps:


Server Requirements:

All Exchange 2013 Client Access Servers to be updated to Exchange Server 2013 SP1 (or later).


Client Requirements:

Outlook 2013 SP1 or Outlook 2010 SP2 with updates KB2956191 and KB2965295 (April 14, 2015).



.NET 4.5.1



MAPI/HTTP is a new endpoint on CAS and can utilize both an internal namespace and an external namespace. 



The certificate used in Exchange will need to include both the internal and external MAPI/HTTP virtual directories to avoid any user certificate prompts, thus consider if the names exist on your certificates.


Enable MAPI/HTTP Configuration:

Enabling MAPI/HTTP is an organizational configuration in Exchange, you won’t have the ability configure this for a subset of servers. If you require more specific control you can control the client behavior with a registry key.

Get-OrganizationConfig | fl mapi*

Set-OrganizationConfig -MapiHttpEnabled $True



An important consideration is to verify load balancers, reverse proxies, and firewalls are configured to allow access to the MAPI/HTTP virtual directories.


IIS Authentication



Virtual directory configuration   

Set-MapiVirtualDirectory –Identity “MSEXCHCAS01\mapi (Default Web Site)” -InternalUrl –ExternalUrl -IISAuthenticationMethods NTLM,Negotiate

Testing – Test MAPI over HTTP connections

1. Test with the Test-OutlookConnectivity cmdlet

Use this command to test MAPI/HTTP connectivity:

Test-OutlookConnectivity -RunFromServerId Contoso -ProbeIdentity OutlookMapiHttpSelfTestProbe


2. Inspect MAPI/HTTP server logs

Administrators can review the following MAPI/HTTP log files to validate how the configuration is operating:






%ExchangeInstallPath%Logging\MAPI Client Access\


%ExchangeInstallPath%Logging\MAPI Address Book Service\

3. Check Outlook connection status on clients

You can also quickly verify that the client is connected using MAPI/HTTP. The Outlook Connection status dialog can be launch by CTRL-right clicking the Outlook icon in the notification area and selecting Connection Status. Here are the few key fields to quickly confirm the connection is using MAPI/HTTP.




HTTP (v/s RPC/HTTP for Outlook Anywhere)

Proxy Server


Server name

Actual server name (v/s GUID for Outlook Anywhere connections)

Rollback Plan

We should not need to roll anything back, as Outlook 2013 will see the AutoDiscover XML payload (either EXPR or EXCH records) and then adjust / connect accordingly.

We can force Mapi/Http to be disabled by the clients by modifying the registry entries. Using EPO/SCCM the registry can be pushed to clients.

To disallow MAPI/HTTP and force RPC/HTTP to be used.



To allow MAPI/HTTP simply delete the MapiHttpDisabled DWORD, or set it to a value of 0 as below.



If users are not able to connect using MAPI/HTTP then we need to check if the below registry is exists with the value “1” then we need to either change the value to “0” or delete it.


Users will get a prompt to restart outlook. Outlook client detects the new connection path and prompts the user to restart, then it will use MAPI/HTTP to communicate with Exchange.

If MAPI over HTTP is enabled at the organization level but disabled for a mailbox, that mailbox will use Outlook Anywhere connections.

The following example enables MAPI over HTTP connections for a single mailbox:

Set-CasMailbox “mailbox name” -MapiHttpEnabled $true

Leave a Reply

Your email address will not be published. Required fields are marked *