Mail system tweaks HOWTO for sme server
Release supported: sme 6.0, 6.0.1
Author: Ray Mitchell - mitchellcpa_AT_yahoo.com.au
Updated: 3 May 2005 v1
Problem:
Your sme server slows down & even stops due to heavy mail loads and you want to control how many messages are being processed at the same time.
You also have Clamav & Spamassassin operating and these also slow down & stop your server due to heavy mail loads and you want to control how many messages are being processed at the same time.
Other problems:
Reject spam using RBL blocking. This is the feature that Jesper Knudsen uses in his Spam Filter contrib.
http://www.contribs.org/contribs/rmitchell/smeserver/howto/Spam%20blocking%20HOWTO%20using%20smtpfront-qmail%20for%20sme%20server.htmManage email aliases for virtual domains see
http://www.contribs.org/contribs/rmitchell/smeserver/howto/virtual%20domain%20email%20aliases%20HOWTO%20for%20sme%20server.htmControl mail to multiple virtual domains & invalid addresses & configure mail blocking rules see
http://www.dungog.net/sme/files/index.phpControl spam using greylisting. Opinions vary as to the effectiveness of using this.
http://lists.contribs.org/mailman/public/devinfo/msg07912.htmlSome of the above have been incorporated into sme 6.5 & 7.0
Solution:
Make the adjustments outlined in this HOWTO & install the above mentioned rpms or edit configuration by following the HOWTOs or instructions as available.
Thanks:
This HOWTO is based on forum posts, emails and my own investigations, thanks particularly to Gordon Rowell, Charlie Brady & Anthony (meanlocha) and to the creators of the various contribs, features and HOWTOs. I have just collated the information into one location and tidied up & clarified the original instructions.
Qmail ConcurrencyLocal & ConcurrencyRemote settings
These will affect the number of messages that are processed concurrently by qmail (ie from qmail) for messages to & from local addresses and for messages to & from remote (external) addresses.
The settings suggested below are OK for a slow connection (and/or a slow server), you can experiment with them to find what suits your situation the best.
Note that if you have a fast connection & a fast server with a heavy mail load, you may wish to increase the values to speed up mail delivery.
The default values are:
ConcurrencyLocal 20
ConcurrencyRemote 10
/sbin/e-smith/db configuration setprop qmail ConcurrencyLocal 5
/sbin/e-smith/signal-event email-update
/etc/init.d/qmail restart
/sbin/e-smith/db configuration setprop qmail ConcurrencyRemote 3
/sbin/e-smith/signal-event email-update
/etc/init.d/qmail restart
To check the settings do:
/sbin/e-smith/config show qmail
qmail=service
ConcurrencyLocal=5
ConcurrencyRemote=3
status=enabled
smtpfront-qmail concurrent processes setting
This will affect the number of concurrent smtpfront-qmail processes (ie messages from smtpfront-qmail into qmail).
The setting suggested below is OK for a slow server, you can experiment with it to find what suits your situation the best.
This setting is not currently controlled by a database entry, but by creating a custom template fragment.
mkdir -p /etc/e-smith/templates-custom/var/service/smtpfront-qmail/runenv
cd /etc/e-smith/templates-custom/var/service/smtpfront-qmail/runenv
pico Concurrency
add following details
CONCURRENCYREMOTE=4
Alt C to save, alt X to exit
/sbin/e-smith/signal-event email-update
Spamassassin processes setting
If you have Spamassassin (& Clamav) running these can consume quite a lot of resources on your server. Spamassassin is particularly processor and memory intensive and can cause minimum configuration servers to stop, with even moderate amounts of mail.
To configure Spamassassin daemon to process only two email messages at a time do the following, keeping in mind that this will severely limit email throughput:
Change (edit) /etc/sysconfig/spamassassin to contain the following and restart spamassassin:
pico /etc/sysconfig/spamassassin
add following details
SPAMDOPTIONS="-d -m2"
Alt C to save, alt X to exit
/etc/init.d/spamassassin restart