Cron | Sys Sandbox

How to trim/pack Spamassassin´s auto-whitelist

The problem: if a mailbox has spam filtering enabled, Spamassasin creates and maintain an auto-whitelist for each of it, and this file increases in time. Generally, every admin wants to trim it or limit it’s size.

Solution 1: On Debian Etch servers running Plesk / QMail & Spamassassin, each mail user has it’s own config files /var/qmail/mailnames/domain/user/.spamassassin. You can add bayes_expiry_max_db_size to each user local.cf or default.cf, but it’s not a global solution and it’s hard to maintain to new users.

Solution 2: Another approach is to run a job (let’s say weekly) to automatically trim the auto-whitelist for all mail users on the server. It’s fast, easy … and you can forget about this in the cron job

After a bit of googling, we found a script to trim old and unused records from an auto-whitelist file here. (in the rest of the article, we’ll assume that the above script is saved as /root/bin/trim-spamassasin-auto-whitelist and it’s made executable with chmod +x)

So far, so good, but the above script works on only one given auto-whitelist.

We can use some bash/sh scripting to find all the mail users settings and apply the trimming to every file, as follows:

#!/bin/sh

# Trim old records and unused space from mail users's .spamassasin/auto-whitelist
# (c) 2008 Frontline softworks, www.frontline.ro
# Visit http://sandbox.frontline.ro for updates

# Trim Utility Location
# Get if from http://www.deepnet.cx/~kdeugau/spamtools/trim_whitelist
TrimUtility='/root/bin/trim-spamassasin-auto-whitelist'

# Users mail storage folder
UsersMail='/var/qmail/mailnames/'

# Auto-whitelist file name
AutoFileName='auto-whitelist'

# Find all Plesk users auto-whitelist
for file in `find $UsersMail -type f -name $AutoFileName`; do
    # Run the trim tool on this mailbox
    # See http://www.deepnet.cx/~kdeugau/spamtools/trim_whitelist
    $TrimUtility $file;

    # After the file is trimmed, there is an '-old' file which we don't need it anymore
    if [ -e $file'-old' ]; then
        rm $file'-old';
    fi;
done

Save the above script in /etc/cron.weekly and wait for the weekly run.

Have fun playing …

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