[Mailman-Users] list too big? Some Sendmail Optimizations

[Jon Carnes]

As far as Sendmail optimizations go, I've found the following
optimizations are sufficient for most folks (even my larger clients):

http://www.trilug.org/~jonc/mailserver/PartIII.html

The following are noteworthy settings inside the sendmail.cf file that
you may wish to change at one time or another:

O MaxMessageSize=1000000 - this is the maximum message size in bytes; by
default there is no limit.

O LogLevel=9 - this controls the amount of information that goes into
the log files.

O Timeout.iconnect=5m - Used to weed out slow hosts. Definitely change
this. I recommend trying 5 seconds (O Timeout.iconnect=5s). This value
is the timeout for the initial connection. If it fails the initial
connection then it moves that host to the rear of the queue and when its
turn comes again in the queue it will use the more generic
"Timeout.connect" value.

O Timeout.helo=5m - The time the server will wait for the HELO command
to complete (initial connection). The RFC's call for 5 minutes, but in
my opinion that is too long. Still, to be conservative I wouldn't make
it smaller than 2 minutes.

O Timeout.mail=10m - Timeout for the response to the MAIL command. The
RFC specifies a minimum of 5 minutes. I would use the minimum, though
some folks set this as low as 2 minutes.

O Timeout.datainit=5m - Timeout for the response to the DATA command.
The RFC specifies a minimum of 2 minutes. I would use the minimum.

O Timeout.ident=0 - You really want to check this and make *sure* that
it is zero, otherwise sendmail wastes that many seconds attempting to
use ident.

O DefaultUser=8:12 - the UserID:GroupID that Sendmail runs as

O QueueLA=8 - load average at which Sendmail simply queues up new
messages, this is a good tweaking parameter

O RefuseLA=12 - load average at which Sendmail starts to reject
connections, this is needs to be modified if you modify QueueLA

#0 MaxDaemonChildren=0 - maximum number of child processes allowed at
one time.

O DeadLetterDrop=/var/tmp/dead.letter - where to save bounces if all
else fails (and this does happen if the system runs out of space on the
/var volume, so you might want to point this to another volume.

#O MaxRecipientsPerMessage=100 - the maximum number of recipients in a
message. 

HtH - Jon Carnes