"I run a Postfix-based mail server that services a few hundred users with an average load of a couple of thousand legitimate messages a day -- but thanks to spam, the actual load on the server is much higher. I use Realtime Blackhole Lists (RBL) and Distributed Checksum Clearinghouse (DCC) clients on Postfix and SpamAssassin to reduce the impact of spam."

This tutorial describes how to scan emails for image spam with FuzzyOCR on a Fedora 12 server. FuzzyOCR is a plugin for SpamAssassin which is aimed at unsolicited bulk mail containing images as the main content carrier. Using different methods, it analyzes the content and properties of images to distinguish between normal mails (ham) and spam mails.

This tutorial describes how to scan emails for image spam with FuzzyOCR on a Debian Lenny server. FuzzyOCR is a plugin for SpamAssassin which is aimed at unsolicited bulk mail containing images as the main content carrier. Using different methods, it analyzes the content and properties of images to distinguish between normal mails (ham) and spam mails.

Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.

Spam is a plague on the Internet. It’s constant and unending. Some ISPs and free web mail providers offer anti-spam services but if you’re running your own mail server, accepting mail to your own domain, you have to work out your own solution. Can open source compete with the big boys? When it comes to spam, is there a free lunch?

There is currently a lot of spam where the spam "information" is attached as .pdf or .xls files, sometime also hidden inside a .zip file. While these spam mails are not easy to catch with e.g. SpamAssassin or a Bayes filter, the ClamAV virus scanner can catch them easily when it is fed with the correct signatures as ClamAV is built to scan mail attachments.

This tutorial describes how to scan emails for image spam with FuzzyOCR on an Ubuntu 9.10 server. FuzzyOCR is a plugin for SpamAssassin which is aimed at unsolicited bulk mail containing images as the main content carrier. Using different methods, it analyzes the content and properties of images to distinguish between normal mails (ham) and spam mails.

"Current Spam fighting techniques like for example SpamAssassin are reactive. SpamAssassin uses a rule based approach and a Bayesian filter.[...]Bayesian filtering requires to collect a rather large amount of mail messages before messages can be filtered. This illustrates that reactive Spam fighting is no real solution."

"(draft for an upcoming book called Wicked Cool Emacs)

Ah, spam, the bane of our Internet lives. There is no completely reliable way to automatically filter spam. Spam messages that slip through the filters and perfectly legitimate messages that get labelled spam are all part of the occupational hazards of using the Internet..."