Topic Last Modified: 2007-05-16

Failover Clustering is a feature of Windows Server 2008, Enterprise operating system. For more information about how to install Failover Clustering, see your Windows Server 2008, Enterprise documentation.

A server cluster is a group of independent computer systems, known as nodes, working together as a single system to make sure that mission critical applications and resources remain available to clients. Server clusters provide high availability. High availability in a Simple Mail Transfer Protocol (SMTP) server cluster means that, if one virtual server fails, its work is dispersed to the remaining virtual servers in the cluster. This makes sure that mail service is not interrupted. The other benefit of server clusters is the failover of server resources, which is when a virtual server goes down and another one comes online to assume its role.

In clustering, a node is a system that has a working installation of Windows Server 2008, Enterprise and the Failover Clustering feature. We recommend creating a new virtual server on your node for clustering, instead of reconfiguring your default SMTP virtual server.

For more information about Failover Clustering and server clusters, see Help and Support. That documentation contains detailed information about how to set up and administer server clusters.


To set up an SMTP virtual server for clustering

  1. If necessary, change the default startup setting of the SMTP service to Manual. For instructions about how to change the default startup setting, see Change the Default Startup Setting.

  2. Before you create a new virtual server, start Microsoft Management Console, right-click the default SMTP virtual server, and then click Properties. For instructions about how to start Microsoft Management Console, see Start Microsoft Management Console.

  3. On the General tab, click Advanced.

  4. Under IP address, click (All Unassigned) then click Edit.

  5. In the Identification dialog box, change the TCP port number from the default port 25. Any unassigned port will work. It is important to change this port number to avoid conflicts with the new SMTP virtual server you will be creating for clustering. Type the new port number (make sure that it is unique) and then click OK.

  6. Create a new SMTP virtual server. For instructions, see Create Additional SMTP Virtual Servers. After it is created, you must manually start it. Make sure that you use the default TCP port on the new virtual server, port 25.

    When you reach the Select Home Directory screen of the New SMTP Virtual Server Wizard, make sure that you type paths to the shared resource that will be used in clustering. Do not type paths to a local hard disk.
  7. Run the IIS Synchronization command to synchronize all IIS information on your node with the other nodes in the server cluster. At a command prompt, open the \Windows\System32\Inetsrv directory on your node and type iissync servername, where servername is another node in the server cluster. For more information about the IIS Synchronization command, see your IIS documentation.

  8. With the server cluster nodes synchronized, you may still have to check the TCP port numbers on your newly created SMTP virtual server and also on the default virtual server. Specifically, when you view your local node from other nodes in the server cluster, make sure that the TCP port settings are identical to how you set them on the local node. On all nodes, the default SMTP virtual server should no longer be pointing to the default port 25, while the new SMTP virtual server should be assigned port 25. Settings must be identical on every node for clustering to work.

  9. Start Failover Cluster Manager. Follow the wizard and associate a resource type to the new SMTP virtual server.

    In the Parameters dialog box, make sure that you select your new SMTP virtual server from the drop-down menu, and not the default SMTP virtual server. For more information about Failover Cluster Manager, see Help and Support.