How does MailMarshal manage its Sender queue?

This article applies to:

• Trustwave MailMarshal (SEG)

Question:

How does MailMarshal manage its Sender queue?

Information:

In MailMarshal 6.0 and above, the maximum messages limit for the active sender queue defaults to 50,000. The Sender queue has been logically divided into high priority and low priority messages (not to be confused with the priority in the message header). Priority in this case refers to message queuing.

In the main queue there is a default limit of 50,000 messages and, for the low priority queue, a default limit of 10,000. The low priority queue is a subset of the main queue, so if the main queue is exhausted, then the low priority queue is also full.

Messages are categorized as low priority if they meet any of the following criteria:

• A notification message generated by MailMarshal (e.g. delivery notifications, delay notifications, rules triggered notifications).
• (prior to 6.4 only) It appears to be a standard message but it has no return-path. This is to handle those cases where the Non-Deliver Reports (NDRs) are generated by the internal target host (e.g. Microsoft Exchange).

MailMarshal will only queue a maximum of 10,000 low priority messages, but up to 50,000 normal messages. The Sender threads are throttled to only work on a smaller number of low priority messages to preserve resources for the delivery of standard legitimate email.  

Notes:

The limitation (10,000 or 50,000) only affects the number of messages that MailMarshal is actively attempting to send. MailMarshal will continue to accept and process messages unless it runs out of disk space. If more than the allowed number of messages have been processed by the Engine, the excess messages remain in the MailMarshal ProcessedOK directory until the queues are reduced.