5.2. Increasing Your Softlimit
If you try to send an email message, you will most likely receive an
error from your client. The error message will say something that includes
451 qq temporary problem (#4.3.0)
If you followed Life with qmail, you then have a memory limit set in the
/var/qmail/supervise/qmail-smtpd/run file. Look for the line that contains
softlimit. It should look similar to this:
exec /usr/local/bin/softlimit -m 2000000 \
This example sets the memory limit for qmail-smtpd to 2M. After all of
your changes qmail-smtpd is now running the entire Perl interpreter, and
ClamAV. 2M will never be enough.
Each system is different, and has different requirements. It will take
some experimenting on your part to find the correct value for your system's
softlimit. Do not set softlimit to some high value! You are asking for
trouble if you do this. To find the minimal value for your system, I
recommend the following steps:
Once you have found the minimum, I recommend increasing that by 1.5M,
just for times that your email server has a heavy load.
After that just create a daily cronjob that runs
/var/qmail/bin/qmail-scan-queue.pl -z to cleanup any dropped SMTP sessions
that may be lying around in /var/spool/qmailscan.