The sys admin's daily grind: SA-Update
New Order
SA-Update helps beleaguered admins face the onslaught of consumer trash.
Spammers must be creative with the structure and content of their junk mail if they want to guarantee the dislike of any PC user anywhere in the world. Because I like to fight spammers on even terms, my SpamAssassin's filter rules need regular updates. Fortunately, I can turn to many channels for ammunition.
SA-Update
The tool that retrieves the updates and copies them to the right spot goes by the name of SA-Update [1].
A GPG key prevents various manipulation techniques such as DNS spoofing. To rejuvenate the default channel, updates.spamassassin.org, I first need the matching public key:
wget http://spamassassin.apache.org/updates/GPG.KEY gpg --import GPG.KEY sa-update --import GPG.KEY
Create Files
Next, I create two files in the SpamAssassin folder. One of them, channels.text, lists the update channels. The second, keys.text, holds the GPG key IDs that I need for secure access. A call to
sa-update -D --channelfile/etc/spamassassin/channels.text--gpgkeyfile /etc/spamassassin/keys.text
starts the update. The -D parameter tells SA-Update to display debug information. Without this parameter – SA-Update is as taciturn as Charles Bronson's character Harmonica [2] – there is no such thing as your average verbose mode.
Filters, Please!
The return value gives an easy method of checking for a successful update. A return value of 0 means that SA-Update has added new filter rules. A value of 1 means that the ruleset was already up to date. A value of 4 or more indicates an error, and that means I need to check the debug output more closely.
To improve the spam detection rate, I like to add channels such as OpenProtect [3] or Daryl O'Shea [4]. A useful overview of the rules of the SpamAssassin Rules Emporium (SARE) are available online [5], and the default ruleset is explained in detail [6]. The filter rule short forms appear in the mail logs; thus, you can tell at a glance what SpamAssassin doesn't like about a message and which ruleset the tool used (Figure 1).
The most important question is, "Is it worthwhile?" Definitely! My spam filter's detection rates benefit considerably by extending the rulesets. Still, I like to keep an eye on the logfiles: The danger of false positives grows with each new filter rule you add.
Infos
- SA-Update: http://wiki.apache.org/spamassassin/RuleUpdates
- "Once Upon a Time in the West" ("C'era una Volta il West"), 1968, http://www.imdb.com/title/tt0064116/
- OpenProtect: http://saupdates.openprotect.com
- Daryl O'Shea: http://daryl.dostech.ca/sa-update/sare/sare-sa-update-howto.txt
- SARE: http://www.rulesemporium.com/rules.htm
- Default ruleset: http://spamassassin.apache.org/tests_3_2_x.html
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Canonical Bumps LTS Support to 12 years
If you're worried that your Ubuntu LTS release won't be supported long enough to last, Canonical has a surprise for you in the form of 12 years of security coverage.
-
Fedora 40 Beta Released Soon
With the official release of Fedora 40 coming in April, it's almost time to download the beta and see what's new.
-
New Pentesting Distribution to Compete with Kali Linux
SnoopGod is now available for your testing needs
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.
-
ZorinOS 17.1 Released, Includes Improved Windows App Support
If you need or desire to run Windows applications on Linux, there's one distribution intent on making that easier for you and its new release further improves that feature.
-
Linux Market Share Surpasses 4% for the First Time
Look out Windows and macOS, Linux is on the rise and has even topped ChromeOS to become the fourth most widely used OS around the globe.
-
KDE’s Plasma 6 Officially Available
KDE’s Plasma 6.0 "Megarelease" has happened, and it's brimming with new features, polish, and performance.
-
Latest Version of Tails Unleashed
Tails 6.0 is based on Debian 12 and includes GNOME 43.
-
KDE Announces New Slimbook V with Plenty of Power and KDE’s Plasma 6
If you're a fan of KDE Plasma, you'll be thrilled to hear they've announced a new Slimbook with an AMD CPU and the latest version of KDE Plasma desktop.
-
Monthly Sponsorship Includes Early Access to elementary OS 8
If you want to get a glimpse of what's in the pipeline for elementary OS 8, just set up a monthly sponsorship to help fund its continued existence.