Changes in version 220.127.116.11 (February 8, 2008)
In all previous versions of Alligate, the SMTP service (AgSMTPSvc.exe) was used to handle all incoming SMTP traffic as well as delivering message via SMTP to your mail server. The following outlines the basic flow of data.
Messages come in from the Internet and are received by the Alligate SMTP service.
The received message is saved as a pair of files, one containing envelope information and the other one containing the actual message data. See also:Email Message Files
If you are using Alligate as a stand alone gateway, the message file pair is saved in the ..\Alligate\Spool directory.
If you are using Alligate with the optional Alligate Anti-spam plug in, the message file pair is saved in the ..\Alligate\Drop directory for processing by the filtering system. If the message is "approved" for delivery, the filtering system will move the message file pair to the ..\Alligate\Spool directory.
Once the message is in the Spool directory, it is basically in line for delivery to your mail server. A separate spooler service (AgSpoolSvc.exe) is provided to manage message spooling. The spooler service monitors the ..\Alligate\Queue folder where message file pairs are placed for final delivery. The spooler service is designed to feed messages to the Queue at a consistent, but metered rate. This is done to reduce the overhead required of the SMTP service to manage the potentially large numbers of files awaiting delivery at any given time.
Beginning with this release, we are providing a new service called the SMTP Delivery Agent (AgSMTPDA.exe). The Delivery Agent (or DA) is completely dedicated to performing the final delivery from Alligate to your mail server. Because it is a totally separate service, and does not need to handle incoming messages at the same time, we feel that this mechanism will not only be more efficient, but will offer a greater degree of reliability. This file is now part of the distribution package and is also contained in the in any update ZIP files.
For the time being, use of this new service is optional. If you prefer, you can continue to use Alligate's original message processing mechanism. However, at some point, use of the delivery agent will become the default mechanism and be mandatory.
For more information, please see Alligate Replaceable Delivery Agent