As of V8.12 sendmail it is possible to group queues according to selected criteria, and then to process each group with custom settings. This versatile ability is enabled and tuned with:
The QUEUE_GROUP mc configuration command, which defines queue groups and sets their group properties
queuegroup mc feature,
which allows you to select queue groups based on recipient hosts via
the access database
More sophisticated queue group selections, which you can make by writing your own rule sets
You can best tune queue groups by first understanding their limitations. We cover these topics in this section, but first we need to briefly discuss the default queue group.
Prior to V8.12 sendmail there were no queue
groups. Instead, every
-q command and every queue
option (such as
QueueDirectory) applied to all the
queue directories you had.
Beginning with V8.12, sendmail offers a way to
define both multiple queue directories and a way to group them by
function or specialty. For compatibility with old versions, a special
queue group named
mqueue is the default queue
group. It takes on all the properties of every
command, and every queue option, just like before.
When you later declare particular queue groups (as we show in the next section), those additional groups take all their properties from the default group, unless you override a particular property with a specific equate. Those equates and the command-line arguments or options ...