Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Win32_Service Microsoft Windows® Management Instrumentation (WMI) class to determine whether the Microsoft Exchange Routing Engine service (RESvc) and the Simple Mail Transfer Protocol (SMTP) service (SMTPSVC) are running. The Exchange Server Analyzer displays an error if the Exchange Server Analyzer finds that either of the following conditions is true:

If RESvc is not running on all Exchange servers that relay messages, routing problems may occur. An Exchange Server configuration that relays messages without RESvc running is not a supported configuration.

Like Exchange 2000 Server, Exchange Server 2003 uses a link state routing algorithm and a routing protocol to propagate link state information in the form of a link state table. The link state table is stored in memory on all Exchange 2000 Server and Exchange Server 2003 servers in the organization.

A link state algorithm provides the following advantages:

Exchange Server collects the following information from the link state table:

Exchange Server uses this information to determine the route with the lowest cost for the destination address. If a connector along the route with the lowest cost is unavailable, Exchange Server determines the best alternative route on the basis of costs and connector availability. RESvc is required for link state routing.

To correct this error, you must configure RESvc to start automatically. You also must make sure that RESvc is running during production hours.

To correct this error
  1. Click Start, point to Programs, point to Administrative Tools, and then click Services.

  2. In the list of services, right-click Microsoft Exchange Routing Engine, and then click Properties.

  3. On the General tab, on the Startup type menu, select Automatic, and then click OK.

  4. Right-click Microsoft Exchange Routing Engine, and then click Start.

For more information about routing messages in Exchange Server 2003, see the Exchange Server 2003 Transport and Routing Guide (