Applies to: Exchange Server 2007 SP3, Exchange Server 2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2007-01-31

Microsoft Exchange uses queues to hold messages as they are being processed for routing and delivery. The Queue Viewer is a tool that helps you maintain and administer your organization's messaging queues and identify mail flow issues. The Queue Viewer is available on all Exchange 2007 servers with the Hub Transport or Edge server role installed.

You must develop a queue baseline so that you can identify the difference between normal behavior and abnormal behavior for your organization. Typically, on-demand use of the Queue Viewer is the result of a support call indicating that e-mail delivery is slow or a message has not been delivered.

For more information about the Queue Viewer, see Using the Queue Viewer to Manage Queues. For more information about each queue in Exchange, common causes of problems in each queue, and how you can troubleshoot mail flow issues, see Microsoft Knowledge Base article 823489, "How to Use Queue Viewer to troubleshoot mail flow issues in Exchange Server 2003."

Using the Queue Viewer

You can use the Queue Viewer to check for the following:

  • Messages that are queued for extended periods of time   Unless an Exchange Server 2007 handles an extremely high volume of e-mail messages, the server will not typically have queued messages for any extended duration. Extended periods of queuing typically indicate a system issue that warrants your attention. Review your performance metrics to see if some other performance issues are causing e-mail messages to queue. If not, look for connectors or servers that are not functioning. SMTP protocol logging might also help you discover the problem.

  • Peaks in queued messages   Spikes in queued messages can occur when someone sends:

    • A message to a large distribution list.

    • An extremely large message to many people.

    • A message whose destination is across a slow network link.

These conditions are not cause for alarm. However, you must review the security of your Exchange organization if either of the following conditions exists:

  • A large volume of messages is queued to one recipient or e-mail address   A large volume of messages queued to one recipient or e-mail address can be a symptom of a spam attack on an e-mail loop or a denial-of-service (DoS) attack.

  • A large volume of messages is queued to a specific server or domain   A large volume of messages queued to a particular server or domain indicates that a server is down, a service is stopped, a domain is unreachable, or a network disruption is preventing the system from establishing a connection.

For More Information

For information about other operations tasks that you might want to perform, see As Needed Tasks.

For information about queues in Exchange 2007, see Managing Queues.