Untangle bundles common open-source applications for blocking spam, spyware, viruses, adware and unwanted content on the network in one single Linux distribution. It can be integrated into existing networks either as a router or as a transparent bridge (directly behind the router, but before the switch that connects the client PCs with the router). The best thing about Untangle is that you do not have to reconfigure the client PCs - Untangle works out of the box.

mod_defensible is an Apache 2.x module intended to block spammers/hackers/script kiddies using DNSBL servers. It will look at the client IP and check it in one or several DNSBL servers and return a 403 Forbidden page to the client. This guide shows how to install and use it with Apache 2 on a Debian Etch server.

This article explains how you can download additional SpamAssassin rulesets resp. automatically update these rulesets with a shell script called RulesDuJour. These additional rulesets can increase your spam recognition rate dramatically. Most of the rulesets that RulesDuJour supports can be found on the SA Rules Emporium web site.

This document describes how to install a Postfix mail server that is based on virtual users and domains, i.e. users and domains that are in a MySQL database. I will also demonstrate the installation and configuration of Courier (Courier-POP3, Courier-IMAP), so that Courier can authenticate against the same MySQL database Postfix uses. The resulting Postfix server is capable of SMTP-AUTH and TLS and quota (quota is not built into Postfix by default, I will show how to patch your Postfix appropriately). Passwords are stored in encrypted form in the database (most documents I found were dealing with plain text passwords which is a security risk). In addition to that, this tutorial covers the installation of Amavisd, SpamAssassin and ClamAV so that emails will be scanned for spam and viruses.

This document describes how to integrate ASSP (Anti-Spam SMTP Proxy) with embedded ClamAV into a mail server based on Postfix featuring virtual users and domains, i.e. users and domains that are in a MySQL database.

This article describes how to integrate DSPAM with embedded ClamAV into a mail server based on Postfix featuring virtual users and domains, i.e. users and domains that are in a MySQL database. DSPAM is a scalable and open-source content-based spam filter. The setup shown here is suitable for Debian Etch servers.

This article shows how you can install and use POPFile to classify incoming emails on an Ubuntu Feisty Fawn desktop. It is a POP3 proxy that fetches your mails from your mail server, classifies them and passes them on to your email client. Of course, POPFile must be trained to properly classify emails.

A blacklist usually refers to a list of email or IP addresses known to send spam emails or some other type of unsolicited messages. Such lists are currently used by mail servers for filtering incoming emails and blocking the ones listed, in order to improve mail security and integrity. The blacklist is also the opposite of what is called a whitelist.

This document describes how to install a Postfix mail server that is based on virtual users and domains, i.e. users and domains that are in a MySQL database. I will also demonstrate the installation and configuration of Courier (Courier-POP3, Courier-IMAP), so that Courier can authenticate against the same MySQL database Postfix uses.

The last few weeks have seen a dramatic increase in spam (once again). Estimates say that spam makes now up for 80 - 90% of all emails, and many mail servers have difficulties in managing the additional load caused by the latest spam, and spam filters such as SpamAssassin do not recognize large parts of that spam as they did before. Fortunately, we can block a big amount of that spam at the MTA level, for example by using blacklists, running tests on the sender and recipient domains, etc. An additional benefit of doing this is that it lowers the load on the mail servers because the (resource-hungry) spamfilters have to look at less emails.