If you are trying to troubleshoot mail flow do the following: You can use Diagnostic Logging to determine the root of a transport issue. To enable Diagnostic Logging on the MSExchangeTransport service, follow these steps: 1. Start Exchange System Manager. 2. Navigate to the server object. 3. Right-click Server object, and then click Properties. 4. Click the Diagnostic Logging tab. 5. Under Categories, click MSExchangeTransport. 6. Under Logging Level, click the appropriate logging level for the issue you are investigating (minimum, medium, or maximum). <b>MAKE SURE YOU CHANGE TO MINIMUM WHEN YOU HAVE DONE AS CREATES HEAPS OF LOGS</b>. Queue Viewer You can use the Queue Viewer tool to maintain and administer your organization's messaging queues. It can help you identify and isolate mail flow issues. Queue Viewer is available on all Simple Mail Transfer Protocol (SMTP) virtual servers, Microsoft Message Transfer Agent (X.400), and all installed Microsoft Exchange connectors. <b>Exchange 2000</b> To access the queues, follow these steps: 1. Start Exchange System Manager. 2. Use the following path to locate the queue you want to administer: Administrative GroupsAdmin Group NameServersServerNameProtocolsSMTPSMTP virtual serverQueuesQueue When you select the Queues container, you'll see a list of the currently existing queues and the number of messages within each queue. If this is the first time you've ever looked at the queues, you might be in for a shock. You'll probably have several queues related to spam, When a message is destined for a remote domain, Exchange 2000 creates a temporary queue for it. Other messages destined for the same domain are also placed into this temporary queue. This allows Exchange to send multiple messages destined for a common domain in batches rather than having to establish a separate session for every single message. Normally, these temporary queues are deleted as fast as they are created. However, if Exchange is unable to find a route to the destination domain, the queue is preserved and Exchange attempts to resend the messages later. If the messages have not been sent within a specific amount of time, the queue and the messages within it are removed. In Figure A, none of my temporary queues are more than two days old. Also, each queue has either a green check mark icon or a Retry icon to indicate the queue’s status. <b>Some standard troubleshooting steps for tracking down mail failures</b> 1. Determine where the message is stuck. To do this, follow these steps: a. Track the message if it just seems to disappear. See whether it is stuck in the categorizer, the message transfer agent (MTA), the Internet Mail Service, the Badmail folder, or elsewhere. b. Examine the non-delivery report (NDR) for error codes and to see which server and which component is generating the NDR. 2. Examine the server that is mentioned in the NDRs, and make sure that all the services are running. In Exchange System Manager, click Tools, and then click Monitoring and Status to review the status. 3. See which event IDs are in the application event log. 4. Increase diagnostic logging to MAX for the transport components. 5. Examine the error codes in the NDR. Note These errors may give you the solutions, such as checking the Domain Name Service (DNS) or network connectivity.

If you are trying to troubleshoot mail flow do the following: You can use Diagnostic Logging to determine the root of a transport issue. To enable Diagnostic Logging on the MSExchangeTransport service, follow these steps: 1. Start Exchange System Manager. 2. Navigate to the server object. 3. Right-click Server object, and then click Properties. 4. Click the Diagnostic Logging tab. 5. Under Categories, click MSExchangeTransport. 6. Under Logging Level, click the appropriate logging level for the issue you are investigating (minimum, medium, or maximum). <b>MAKE SURE YOU CHANGE TO MINIMUM WHEN YOU HAVE DONE AS CREATES HEAPS OF LOGS</b>. Queue Viewer You can use the Queue Viewer tool to maintain and administer your organization's messaging queues. It can help you identify and isolate mail flow issues. Queue Viewer is available on all Simple Mail Transfer Protocol (SMTP) virtual servers, Microsoft Message Transfer Agent (X.400), and all installed Microsoft Exchange connectors. <b>Exchange 2000</b> To access the queues, follow these steps: 1. Start Exchange System Manager. 2. Use the following path to locate the queue you want to administer: Administrative GroupsAdmin Group NameServersServerNameProtocolsSMTPSMTP virtual serverQueuesQueue When you select the Queues container, you'll see a list of the currently existing queues and the number of messages within each queue. If this is the first time you've ever looked at the queues, you might be in for a shock. You'll probably have several queues related to spam, When a message is destined for a remote domain, Exchange 2000 creates a temporary queue for it. Other messages destined for the same domain are also placed into this temporary queue. This allows Exchange to send multiple messages destined for a common domain in batches rather than having to establish a separate session for every single message. Normally, these temporary queues are deleted as fast as they are created. However, if Exchange is unable to find a route to the destination domain, the queue is preserved and Exchange attempts to resend the messages later. If the messages have not been sent within a specific amount of time, the queue and the messages within it are removed. In Figure A, none of my temporary queues are more than two days old. Also, each queue has either a green check mark icon or a Retry icon to indicate the queue’s status. <b>Some standard troubleshooting steps for tracking down mail failures</b> 1. Determine where the message is stuck. To do this, follow these steps: a. Track the message if it just seems to disappear. See whether it is stuck in the categorizer, the message transfer agent (MTA), the Internet Mail Service, the Badmail folder, or elsewhere. b. Examine the non-delivery report (NDR) for error codes and to see which server and which component is generating the NDR. 2. Examine the server that is mentioned in the NDRs, and make sure that all the services are running. In Exchange System Manager, click Tools, and then click Monitoring and Status to review the status. 3. See which event IDs are in the application event log. 4. Increase diagnostic logging to MAX for the transport components. 5. Examine the error codes in the NDR. Note These errors may give you the solutions, such as checking the Domain Name Service (DNS) or network connectivity.