Microsoft Dynamics 365 Blog

A common misconception is that if CRM user mailboxes are spread across a number of Exchange servers, then the E-mail Router must be installed on every Exchange server.  In CRM 3.0, this is not true.

Incoming mail is delivered to an individual user’s mailbox as usual.  The Microsoft CRM Rule Deployment Wizard enables a rule to be deployed to each CRM user’s mailbox that will forward mail from the user’s mailbox to a CRM-dedicated mailbox.  The Router monitors only this mailbox (sometimes called a “forward mailbox” or “sink mailbox”) and has to be installed on the same machine as it.

The CRM-dedicated mailbox can be installed on any Exchange server.  The only restriction is that it must be in the same domain (or trusted domain) as the CRM server to enable authentication between CRM and the Router.  The Router should only be installed on the server with the CRM-dedicated mailbox.  Mail can be forwarded from CRM user mailboxes on other servers and even across domains and the internet (as the mailbox will have a regular SMTP email address).

Only one instance of the Router may run on an Exchange server and one CRM-dedicated mailbox can only handle mail for a single CRM implementation.  However, additional CRM-dedicated mailboxes may be created for additional CRM implementations, and the one instance of the Router may monitor multiple pairs.  Only one pair is configured during Router setup, but additional ones can be added using the registry on the Exchange server:

  • Location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSCRMExRouterService

  • Key: MailboxesInfo

  • Key Parameters: crmServerUrl;emailServer;smtpDomain;emailAccount[;forcedelivery]


    The URL of the CRM server associated with the sink mailbox to read from.


    The name of the local Exchange server


    The SMTP domain name of the sink mailbox.


    The account name of the sink mailbox


    An optional flag that should be set to a value of 1.This flag causes emails to be held in the CRM mailbox until the Microsoft CRM server responds once (then the flag will be cleared automatically). Without the flag, if the Router cannot communicate to the Microsoft CRM server and email will be moved to the undeliverable folder in the CRM mailbox after a number of retries trying to deliver to the Microsoft CRM Server. This flag is useful in scenarios where the Microsoft CRM Server is not available (possibly it is not yet installed, upgraded from Microsoft CRM version 1.2, or otherwise not yet ready to process messages).

Many organizations that run multiple CRM implementations (such as us here at Microsoft) centralize all their CRM-dedicated mailboxes onto a single Exchange server to simplify administration.  

A single user may be a member of multiple CRM implementations and can route mail to them all.  They will need rules that will forward their mail to each implementations’ mailbox.

A CRM implementation can accept mail from multiple dedicated mailboxes and multiple Exchange servers.  This tends to be rare as it does not enable many additional scenarios, though is sometimes used for redundancy purposes.  Each additional Exchange server needs to be added to the PrivUser group on the CRM server (as only one is configured during server setup).

Ilana Smith

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