The Mail Queue

The Mail Queue

The Spool directory is also known as "the queue," since it is the place where messages wait to be delivered. Messages in the queue include incoming messages, outgoing messages, and attachments, as well as error messages generated by IMail Server or other mail servers. Also in the spool directory are the IMail Server log files.

Viewing Files in the Queue

To view files in the queue click View Queue on the local host's General tab. The Number of times box shows the number of times IMail Server has attempted to deliver the selected message.

The files in the Spool directory are all plain text and can be viewed using Windows Notepad. Note, however, that if you edit a D (data file) or Q file (message awaiting delivery), you could render the file incompatible with IMail Server.

Files in the Queue

Files in the queue are messages on their way in or out. By looking at the files in the queue, you can determine what stage a message is in; this is indicated by the first character in the file name and the file extension.

Beginning Character in File Name

When a message is in the queue, it is a "data file" whose name begins with D. Data files have matching T, Q, or A files as they get processed.

File name Description

A*.??? A data file undergoing connection filtering and SPF testing; deleted when message is delivered.

D*.??? A data file in process; deleted when message is delivered.

T*.??? A file that matches the data file while the message is inbound; when the message is fully received, the T file is renamed with a Q.

Q*.??? A file that matches the data file while the IMail server attempts to deliver the message.

_*.~?? A locked file that is being processed; these files also have a tilde (~) in the file extension. (If three characters of the file name are nex, the file is being processed via Web Messaging or imail1.exe.)

F*.txt Mail to Fax file.

Normally, messages are processed in a few seconds or a few minutes. However, if there's a problem with delivering a message, the associated files may stay in the queue longer. IMail Server automatically attempts to reprocess messages in the queue each time the Retry Timer reaches zero. If a message is still not delivered by the "number of tries" equals the Number of tries setting on the SMTP tab, the message is returned to the sender.

IMail Server does not delete the data file when a message is not deliverable, not returnable, and there is no postmaster alias (or there is a problem with the postmaster or root alias accounts). Thus, no message is ever truly lost even if it can't be delivered.

If you happen to reboot your system while a message is being received, IMail Server may leave behind the T and the D files. You can use the Spool Cleaner utility to clean up files older than a certain number of days. For more information, see "Cleaning the Spool Directory (isplcln.exe)".

File Extensions

The file extension also indicates the type of file.

.SMD, .SMP, and .RMD file extensions indicate regular mail messages being processed by SMTP.
.FWD and .FWP file extensions indicate forwarded messages.
.LST file extensions indicate messages to subscribers of a list server mailing list.
.TMP are Web Messaging, or Mail to Beeper/Pager, or Mail to Fax files.
.GSE and .GSP file extensions indicate error messages being returned to the senders. These are usually generated by the server (postmaster).
.GSC file extensions are Web Messaging messages.
.VAC file extensions are vacation messages and info manager responses.

Files that contain a tilde (~) in the file extension, such as .~MP and .~MD, are locked files that are in process. These files also have an underscore as the first character in the file name.

Attachments

Attached files also appear in the queue. For multiple attachments, the Windows Explorer naming convention is used, so you could have attach.txt, attach(1).TXT, attach(2).TXT, and so on.

File name	Description
A*.???	A data file undergoing connection filtering and SPF testing; deleted when message is delivered.
D*.???	A data file in process; deleted when message is delivered.
T*.???	A file that matches the data file while the message is inbound; when the message is fully received, the T file is renamed with a Q.
Q*.???	A file that matches the data file while the IMail server attempts to deliver the message.
_*.~??	A locked file that is being processed; these files also have a tilde (~) in the file extension. (If three characters of the file name are nex, the file is being processed via Web Messaging or imail1.exe.)
F*.txt	Mail to Fax file.

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