Hold Queue Test

Whenever a Postfix mail server detects spam messages/malware, then those messages are automatically placed in the hold queue. By default, the administrator defines smtpd access policies, or cleanup header/body checks that may cause messages to be automatically diverted from normal processing and be placed indefinitely in the hold queue. The messages remain in the hold queue until the administrator intervenes. The messages in the hold queue are barred from periodic delivery attempts. Messages can stay in the hold queue longer than the maximum lifetime specified for the hold queue. The old messages in the hold queue can be released only by moving those messages into the maildrop queue. Once the messages are moved into the maildrop queue, the messages will get a new timestamp and will be attempted delivery. The messages that are relatively new in the hold queue can be moved directly to the deferred queue. If the hold queue consists of too many messages, then the hold queue may grow indefinitely and at some point, the queue may not be able to accommodate new messages resulting in a bottleneck of the queue. To avoid such bottlenecks and figure out the exact time duration for which messages are in the hold queue, it is necessary for the administrator to periodically monitor the hold queue. The Hold Queue test helps administrators to identify the time duration from which the hold queue was bombarded with messages.

This test periodically monitors the hold queue of the target Postfix mail server and reports the total size of the queue as well as the split up of the message count in terms of time duration i.e., the number of messages that were in the queue for a specified time duration.

Target of the test : A Postfix mail server

Agent deploying the test : A remote agent

Outputs of the test : One set of results for the target Postfix mail server being monitored

Configurable parameters for the test
Parameters	Description
Test period	How often should the test be executed
Host	The host for which the test is to be configured.
Port	The port at which the specified host listens. By default, this is NULL.
UseSUDO	By default, this flag is set to False indicating that the test does not collect the queue related statistics, by default. If this flag is set to True, then the test uses the sudo command to collect the queue related statistics.
Timeout	Specify the duration (in seconds) beyond which this test should time out in the TIMEOUT text box. The default is 30 seconds.
High Security	In highly secure environments, eG Enterprise could not perform agentless monitoring on a target Postfix server using SSH. To enable monitoring of the target host in such environments, administrators can use the High Security flag. By default, this flag is set to Yes indicating that eG Enterprise will connect to the target host in a more secure way and collect performance metrics. However, administrators can override this setting if required.
Detailed Diagnosis	To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option. The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled: The eG manager license should allow the detailed diagnosis capability Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measures made by the test
Measurement	Description	Measurement Unit	Interpretation
Queue size	Indicates the total size of the queue.	Number	An unusually high number of messages in the queue is indicative of any problem with the corresponding queue or its end points. The Detailed diagnosis of this measure lists the message count for each domain.
Less than 5 mins	Indicates the number of messages that were in the queue for less than 5 minutes.	Number
Between 5-10 mins	Indicates the number of messages that were in the queue for a time duration between 5 to 10 minutes.	Number
Between 10-20 mins	Indicates the number of messages that were in the queue for a time duration between 10 to 20 minutes.	Number
Between 20-40 mins	Indicates the number of messages that were in the queue for a time duration between 20 to 40 minutes.	Number
Between 40-80 mins	Indicates the number of messages that were in the queue for a time duration between 40 to 80 minutes.	Number
Between 80-160 mins:	Indicates the number of messages that were in the queue for a time duration between 80 to 160 minutes.	Number
Between 160-320 mins	Indicates the number of messages that were in the queue for a time duration between 160 to 320 minutes.	Number
Between 320-640 mins	Indicates the number of messages that were in the queue for a time duration between 320 to 640 minutes.	Number
Between 640-1280 mins	Indicates the number of messages that were in the queue for a time duration between 640 to 1280 minutes.	Number
More than 1280 mins	Indicates the number of messages that were in the queue for more than 1280 minutes.	Number	A high value for this measure is a cause of concern as this may be an indication of spam messages and malware which may have been filtered out.