Fast, teachable, learning spam detector
Bogofilter is a trainable email spam detector. Bogofilter takes an email message or other text on standard input, parses it into words, does a statistical check against databases of "good" and "bad" words, and returns a status code indicating whether or not the message is spam. Bogofilter decodes base64 or quoted-printable encoded texts and ignores non-text attachments and HTML comments. The supported database backends are Berkeley DB, QDBM and SQLite3.
Qmail filter for monitoring and intercepting SMTP connections
spamdyke is a filter for monitoring and intercepting SMTP connections between a remote host and a qmail server. Spam is blocked while the remote server (spammer) is still connected; no additional processing or storage is needed. In addition to all of its anti-spam filters, spamdyke also includes a number of features to enhance qmail. Best of all, using spamdyke does not require patching or recompiling qmail!
Dovecot 2.x plugin for spam systems training
The dovecot antispam plugin is aimed to help in spam systems training. Consider the following scenario. Your mailbox is flooded with tons of mail. They are delivered to the configured folders based on the arbitrary spam system judgement. This judgement is not always correct or not always what you would like it to be, however. This is where this plugin comes into play. All you have to do is move the mail into the correct folder. All the rest in order to let the spam system know it made an error will be done automatically by this plugin. It watches for when you move the mail to some folder and acts accordingly. The advantage of this approach is that the mail ends up in the right target folder directly and needs not be touched twice.
Cache earlier sendmail's verdicts for the relays
The skem utility is a sendmail milter, that checks and maintains a list of whitelisted, temporary banned, and permanently blacklisted IP-addresses. How you obtain the entries is up to you, but the included logwatcher module provides one possibility. The list is stored in a directory, each entry being a file (usually -- zero sized) or a symlink (usually -- a "broken" one). Such entries are stored efficiently (within the directory itself) and the directories are searched using the hash tables on modern file systems. At the same time, they can be listed, added, and removed with the simple ls(1), touch(1), and rm(1). This milter does not itself filter spam, instead it memorizes the verdicts issued by your other anti-spam defenses to reduce the system load and resource consumption, by temporarily rejecting the relays suspected of spamming (banned) and, optionally, by permanently rejecting the relays "convicted" of spamming (blacklisted). The idea is to stem the spam from real spam sources, while reducing the ill effects of false-positives to merely delaying, rather than rejecting future messages.
Anti-spam plugin for Postfix (written in C)
Policyd is an anti-spam plugin for Postfix (written in C) that does : o Greylisting, o Sender-(envelope, SASL or host / ip)-based throttling (on messages and/or volume per defined time unit), o Recipient rate limiting, o Spamtrap monitoring / blacklisting, o HELO auto blacklisting o HELO randomization preventation, o Sender mail addresses or domain Sender blacklisting
Collaborative, networked system to detect and block spam
Pyzor is a collaborative, networked system to detect and block spam using identifying digests of messages. Pyzor initially started out to be merely a Python implementation of Razor, but due to the protocol and the fact that Razor's server is not Free Software, I decided to Pyzor should be based upon a new, lighter, more language- independent protocol.
MTA spam prevention program for qmail/postfix/sendmail
Nearly all of today's mail system administrators face spam as their first threat. Because of this, EnderUNIX team has written this small application to automagically monitor malicious spammer activity in your mail server logs. spamGuard is written purely in C, to stop spammers hanging around. The program supports nearly all mostly used MTAs; qmail (both multilog and splogger), sendmail and Postfix.
Roundcube plugin to manage SpamAssassin prefs
Roundcube plugin to manage SpamAssassin preferences. Adds a 'Spam' tab to the 'Personal Settings' to allow the user to change their SpamAssassin preferences. Preferences must be stored in a SQL database. Default preferences are used when no user preference is found.
Fast Content/Anti-virus Scanner for qmail Written in C
Simscan is a simple program that enables qmail-smtpd to reject viruses, spam and block attachments during the SMTP conversation so the email never makes it into your computers. It is completely open source and uses other open source components. Very efficient and written in C.
Tool to generate statistics for spamd of Mail::SpamAssassin
A script that generates statistics about spam you receive at your site. The script parses maillog file, generated by exim/postfix/sendmail and spamd. The script will currently not work with other mailers than exim, postfix or sendmail (contributions will be welcome) or if you do not use spamd.