Connection Problems

When troubleshooting connection problems, it is important to determine the number of connections that are in error.

• If multiple connections are down, check your network topology map for common features of the problem connections, such as a certain server, router, bridge, gateway, or leased line.
• If just one connection is down, concentrate on why the ping message failed to complete the round-trip in time.
Examine the bounce detail of the ping message in the connection's General property page. A long delay between one hop and the next or a long delay at the last hop indicates a bottleneck or failing connection. Refer to your message routing map for components in the path that could be down.

Use other troubleshooting tools to supplement the data from the link monitor. This is essential until at least one ping message on a connection is returned.

• All ping messages should return eventually, unless they are deleted along the route. If a ping message does not return, check the queues in the message transfer agent (MTA) and information stores of the sending and receiving servers. If message tracking is enabled, the message tracking log also provides a trace of the ping message.
• Send a test message and search for it in the queues of servers and gateways along its route. Most problems that cause an alert in the link monitor also generate a large backlog of messages. This task can be made more difficult if there are multiple routes the message could follow. Use your message routing map to narrow the scope of your search.
• Check the queue size on servers in your site. Create a Windows NT Performance Monitor chart file that tracks the queue size on each server and look for one or more servers with large queues.
• Use Windows NT Event Viewer to search application event logs on the link monitor's home server and destination server. To make the search more efficient, filter the display to show only those events between the last successful message and the first link monitor warning. Look for warnings and alerts from the MTA, information store, and directory.
• Start or check a server monitor that is running to see if any servers in the route of the ping message are down, or use Windows NT Server Manager to see if the services are running.
• Use Performance Monitor to check connectors and gateways to see that they are processing mail. Check the messages/sec or messages/hour counters.