dma for Debian
--------------
-1. Deferred delivery by default
+1. Smarthost operation by default - needs to be configured!
+
+After first installing dma, you need to configure it for proper operation -
+whether it should deliver all outgoing e-mail messages through a single
+smarthost or attempt to contact the remote mail servers directly. This should
+be configured through the debconf questions, but you may change the setting
+using the SMARTHOST directive in the /etc/dma/dma.conf file.
+
+2. Deferred delivery possible via a cron job
The dma mail transfer agent may operate in two modes - immediate and
deferred. In both cases, a new dma process is spawned for the delivery
of each outgoing message, and this process lives on until the message is
either successfully delivered or it times out after five days.
-In immediate delivery mode, the new dma process is spawned as soon as
-the message is submitted to the queue. In deferred mode, which is
-the default for the Debian package, the message is left in the queue
-and will only be processed when dma is invoked separately with the "-q"
-command-line option. This is the preferred delivery mode - even though
-there may be slight delays, the queue must still be processed periodically
-anyway (if an immediate delivery is deferred, the message is still left
-on the queue), so there's no harm done in always doing it that way.
+In immediate delivery mode, which is the default, the new dma process is
+spawned as soon as the message is submitted to the queue. In deferred mode,
+the message is left in the queue and will only be processed when dma is invoked
+separately with the "-q" command-line option. This used to be the preferred
+delivery mode for the Debian package - even though there may be slight delays,
+the queue must still be processed periodically anyway (if an immediate delivery
+is deferred, the message is still left on the queue), so there's no harm done
+in always doing it that way.
Hence, the Debian package of dma installs a cron job that attempts to
flush the queue every five minutes. Note that this does NOT mean that
message, and it takes care of reasonable exponential back-off in case of
delivery problems.
-2. Smarthost operation by default - needs to be configured!
-
-After first installing dma, you need to configure it for proper operation -
-whether it should deliver all outgoing e-mail messages through a single
-smarthost or attempt to contact the remote mail servers directly. This should
-be configured through the debconf questions, but you may change the setting
-using the SMARTHOST directive in the /etc/dma/dma.conf file.
+This cron job has no ill effect if dma has been configured for immediate
+delivery - if a message is submitted, a dma process shall be spawned to handle
+its delivery at once, and the cron job will not spawn any additional processes
+or in any way interfere with the running ones. However, if the dma process
+that handles the delivery should die for some reason, or the system should be
+restarted, the cron job will ensure that a new delivery process is spawned in
+due time and the message is not just left in the queue.
3. Double-bounce handling
still has the dma internal format, which is plain text, but is not really
a mailbox :)
- -- Peter Pentchev <roam@ringlet.net> Mon, 21 Jun 2010 11:31:02 +0300
+ -- Peter Pentchev <roam@ringlet.net> Tue, 27 Jul 2010 13:26:48 +0300
projects / people / ms / dma.git / commitdiff
