Difference between revisions of "Spamassassin"

Latest revision as of 16:02, 4 October 2014

[edit] General Improvements

Add razor, dcc and pyzor

Step 1) Add atomic channel:

 wget -q -O - https://www.atomicorp.com/installers/atomic.sh |sh

Step 2) Add razor, dcc, pyzor

 yum install razor-agents dcc pyzor

Step 3) Restart spamassassin

 /etc/init.d/spamassassin restart

[edit] Force spamassassin to scan messages from localhost, when using qmail-scanner

 vi /etc/xinetd.d/smtp_psa

service smtp
{
       socket_type     = stream
       protocol        = tcp
       wait            = no
       disable         = no
       user            = root
       instances       = UNLIMITED
       env             = QS_SPAMASSASSIN="on"
       server          = /var/qmail/bin/tcp-env
       server_args     = /usr/sbin/rblsmtpd -r sbl-xbl.spamhaus.org /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true
}

[edit] Mysql settings for whitelisting

INSERT INTO userpref (username,preference,value) VALUES ('%tsginc.com','whitelist_from','*domain.com');
INSERT INTO userpref (username,preference,value) VALUES ('%tsginc.com','whitelist_from','*@domain.com');

[edit] Limiting Load

Add max_load to /etc/xinetd.d/smtp_psa. SMTP will throttle connections when load reaches a certain point. The per_source flag will limit the maximum number of concurrent connections from a single IP.

service smtp
{
       socket_type     = stream
       protocol        = tcp
       wait            = no
       disable         = no
       user            = root
       max_load        = 5
       per_source      = 2
       instances       = UNLIMITED
       env             = QS_SPAMASSASSIN="on"
       server          = /var/qmail/bin/tcp-env
       server_args     = /usr/sbin/rblsmtpd -r sbl-xbl.spamhaus.org /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true
}

[edit] Updating spamassassin rules and signatures

Note: The ART spamassassin package already does this, if you are not using our RPMs then you will need to setup updates manually.

1. Import the GPG keys of the rule repositories (spamassassin and the SARE rules):

Run these commands as root once to setup the system:

 wget http://spamassassin.apache.org/updates/GPG.KEY
 sa-update --import GPG.KEY
 gpg --keyserver pgp.mit.edu --recv-keys BDE9DC10
 gpg --armor -o pub.gpg --export BDE9DC10
 sa-update --import pub.gpg 

Note: as far as I know sa-update works fine without executing these steps.

2. Run the rule updater

sa-update --allowplugins --gpgkey D1C035168C1EBC08464946DA258CDB3ABDE9DC10 --channel saupdates.openprotect.com --channel updates.spamassassin.org

Note: the OpenProtect SpamAssassin sa-update channel is no longer active, so adding it is useless. Remove it if you configured it before. http://saupdates.openprotect.com/ says: "OpenProtect' SpamAssassin sa-update channel is obsolete since SARE stopped updating their rulesets. Please stop using this channel."

3. (Optional) Compile the rules to make spamassassin run faster

Note: This can take some time to complete and will generate load on your system.

(The steps below are also optional and are useful on systems that use ASL with the real time malware prevention system to help prevent the system from being triggered, the /root/ directory is considered trusted.)

 mkdir /root/tmp
 TMP=/root/tmp 
 export TMP
 TMPDIR=$TMP
 export TMPDIR

This step however is not optional if you want to compile the rules:

 /usr/bin/sa-compile

Note: the re2c package must be installed to compile the rule, if you do not have that package installed you can install it with this command on a RHEL, Fedora or Centos system:

 yum install re2c

4. Restart spamassassin

This step is required. Spamassassin loads the rules on start and failing to do this means your system will not update to the latest rules.

/etc/init.d/spamassassin condrestart

5. (Optional) Setup spamassassin updates in your root crontab

You can also setup your system to do this automatically and safely. Using crontab and the example commands below will setup sa-update to download update and only when an update is downloaded and is sucessful will the system recompile and restart spamassassin. If there are any errors spamassasin will not be restarted and the system will continue to function normally and safely.

Run this command as root to setup the crontab:

crontab -e

Then add the line below:

<MINUTE> <HOUR> * * * sa-update --allowplugins --gpgkey D1C035168C1EBC08464946DA258CDB3ABDE9DC10 --channel saupdates.openprotect.com --channel updates.spamassassin.org && TMP=/root/tmp; export TMP; TMPDIR=$TMP; export TMPDIR; /usr/bin/sa-compile && /etc/init.d/spamassassin condrestart 1> /dev/null

And change <MINUTE> and <HOUR> to numerical values representing the time when you want the update to run, 13 2 for example would be 2:13 AM. Pick your own time so that you are not running your updates at the same time as everyone else (or all of your boxes).

Note: See step 2. The OpenProtect SpamAssassin sa-update channel is no longer active, so don't run sa-update with --channel saupdates.openprotect.com anymore. The RPM package comes bundled with /etc/cron.d/sa-update which updates the SpamAssassin rules daily. I recommend adding the compilation step to this file if you want to compile your rules after updating them; or set up a completely separate cronjob which checks if the rules have been updated and compiles the rules when they're new.