Exchange Mail Transfer Test

Exchange Servers use SMTP as the default transport for messages across servers and to the Internet. All mail that is not being sent from senders and recipients homed on the same server goes through SMTP.

The following steps trace the path of a message:

The message is submitted using MAPI or SMTP
The message is then categorized, which means the Exchange server consults the Active Directory for information regarding its recipients.
The message is routed, which means the Exchange server decides if the message should be delivered locally (the recipient is homed on this server) or to which server should this message be sent (to the Internet, another server, other domains, and so on).
SMTP either delivers the mail locally or queues it for remote transfer

The local and remote queues are key indicators of bottlenecks on the Exchange server. The ExchangeMailTransfer Test monitors both these queues.

This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick Exchange the desired Component type, set Performance as the Test type, choose the test from the disabled tests list, and click on the < button to move the test to the ENABLED TESTS list. Finally, click the Update button.

Target of the test : An Exchange Server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every Exchange server being monitored.

Configurable parameters for the test
Parameters	Description
Test Period	How often should the test be executed.
Host	The IP address of the machine where the Exchange Server is installed.
Port	The port number through which the Exchange server communicates.
IsPassive	If the value chosen is Yes, then the Exchange server under consideration is a passive server in an Exchange cluster. No alerts will be generated if the server is not running. Measures will be reported as “Not applicable’ by the agent if the server is not up.

Measurements made by the test
Measurement	Description	Measurement Unit	Interpretation
Local queue size	This measure indicates the number of messages in the SMTP queue for local delivery.	Number	This measure is close to zero under normal operating conditions. The maximum value should be less than 1000. Also, the queue should remain steady near its average, with small variance. If this measure increases steadily over a period, there is probably a problem with the information store to which the user is trying to deliver. In the majority of cases, a buildup of messages in the Local Delivery queue indicates a performance issue or outages on the server, because the server is no longer able to deliver the incoming mail in a timely manner. This hold up can come from a slowness in consulting Active Directory or in handing messages off for local delivery or SMTP. It can also come from databases being dismounted.
Remote queue size	This measure indicates the number of messages SMTP queue for remote delivery.	Number	This measure is close to zero under normal operating conditions. The maximum value should be less than 1000. Also, the queue should remain steady near its average, with a small variance. The value of this measure may increase if mails are sent to different external domains. A rise in this measure means that value is not being sent to other servers. This failure to send mail can be explained by outages or performance issues with the network or remote servers. Those outages or performance issues are causing the network or remote servers from receiving the mail efficiently.
Current SMTP connections	This measure shows the total number of current inbound connections.	Number	A zero value for this measure either indicates that no SMTP clients are accessing the Exchange server or some network problems exist that is blocking the user requests. A substantial high value for this measure indicates that the SMTP server is overloaded. This problem can be solved by limiting the number of connections to the SMTP virtual server in the Exchange System Manager.
Bad mails	This measure indicates the number of bad mails generated from the time this test was last executed.	Number	A non-zero value for this measure indicates that the mails are not delivered to the destination. This situation may arise due to one of the following reasons: No recipients might have been mentioned for the mail A network failure A general failure in the Exchange server
Data received	This measure shows the rate at which the Exchange server receives data.	KB/Sec	An above normal value for this measure over a period may indicate that the SMTP server is overloaded. Limiting the number of simultaneous connections to the SMTP virtual server in the Exchange System Manager can solve this problem.
Data sent	This measure shows the rate at which the Exchange server sends data.	KB/Sec	A high value over a period is indicative of an excessive use of the SMTP server. Limiting the number of simultaneous connections to the SMTP virtual server in the Exchange System Manager can solve this problem.
Avg message delivery retries	Messages that could not be delivered by the Exchange server are sent to the retry queue. This measure indicates the number of messages entering the retry queue as a fraction of the overall message delivery.	Number	This measure is a good indicator of the general message delivery problems in the target environment. This measure should be close to zero. If a large number of messages are being retried, this measure will approach to 1.
Avg retry messages sent	This measure shows the average number of retries per outbound message sent as a fraction of the overall messages that is being sent from the Exchange server.	Number	This measure should be close to zero under normal operating conditions. If a large proportion of the sent messages are entering the retry queue, this measure will approach to 1.