i had an issue yesterday where almost all the email that was accepted by spamfilter could not be delivered to my outside server.  All this email I assume was placed in a delivery queue.  It appears that it is now being delivered slowly.  My questions are these:

1.  Where is this delivery queue on the server so I can monitor and see how much email is in there?
2.  How often is re-delivery attempted?
3.  For how long? (ie: when will spamfilter give up?)
4.  If spamfilter gives up, what does it do?

Thanks.

By default, if the destination server is offline, SpamFilter will retry every 60 minutes (this parameter is user-definable, as Jeremy correctly pointed out) to deliver the queued emails to your server, indefinitely until it come back online.

Thru a setting in the SpamFilter.ini file however, the “indefinitely” can be changed so that SpamFilter retries for a user-defined number of hours before giving up. The setting is:

;Number of hours SpamFilter will retry to deliver messages in queue to your destination SMTP server if it was unreachable. Enter 0 to try forever until back online.
ExpireRetryQueueHours=0

In addition, you can control how SpamFilter handles SMTP errors encountered when forwarding emails to your server. The following two settings are available in the SpamFilter.ini file:

;Determines if SpamFilter should hold in the queue emails that were rejected by the destination SMTP server with an error in the 4xy range
QueueIfDestinationError400=true

;Determines if SpamFilter should hold in the queue emails that were rejected by the destination SMTP server with an error in the 5xy range
QueueIfDestinationError500=false

When SpamFilter forwards emails to your destination SMTP server, it will employ at most a number of concurrent connections to your server equal to only one fourth of the maximum number of incoming connections in SpamFilter. This is done so as to not overload your mail server.