Originally based off the program qmail-masq, qmail-masq-user uses qmail and qmail-qfilter to change the From: address of outgoing emails to almost any combination of username, domain, or both. The configuration allows you to specify domain catch-alls, user catch-alls, email catch-alls, specific combinations of users and/or domains, and much more.
DynaStop is a utility to examine IPv4 based addresses for Exim and procmail for the purpose of filtering based upon patterns defined by the administrator. This can be a pivotal factor in email filtering and server load management, since dynamic IP addresses are typically used for dial-up, DHCP, and DSL accounts. All of which have a designated mail exchange server through which all outbound mail flows as defined with many, if not most, large Internet service providers.
John the Ripper is a fast password cracker, currently available for many flavors of Unix, Windows, DOS, BeOS, and OpenVMS. Its primary purpose is to detect weak Unix passwords. It supports several crypt(3) password hash types commonly found on Unix systems, as well as Windows LM hashes. On top of this, lots of other hashes and ciphers are added in the community-enhanced version (-jumbo), and some are added in John the Ripper Pro.
Email Security through Procmail (the Procmail Sanitizer) provides methods to sanitize email, removing obvious exploit attempts and disabling the channels through which exploits are delivered. Facilities for detecting and blocking Trojan Horse exploits and worms are also provided.
MailStripper Pro is a mail scanner that aims to remove spam and viruses from incoming mail. It recognises and decodes many obfuscation techniques used by spammers and uses several different mechanisms to recognise spam which are immune to Bayes poisoning, and has achieved real-world success of over 99.8%. It is MTA-independent and does not implant itself into your mail server. Instead, it functions as a proxy, allowing the MTA to reside on a different server.
Logrep is a secure multi-platform tool for the collection, extraction, and presentation of information from various log files. It features HTML reports, multi-dimensional analysis, overview pages, SSH communication, and graphs, and supports 25 popular systems including Snort, Squid, Postfix, Apache, Sendmail, syslog, iptables/ipchains, xferlog, NT event logs, Firewall-1, wtmp, Oracle listener, and Pix.
Mail2sh makes it possible to carry out shell commands by email. Email is sent to a particular user on your host and the commands will be carried out if the user and password given matches ones in /etc/passwd. Commands are executed with the user's privileges, and combined with a PGP module ensures a certain level of security for use. Note that the system is not natively encrypted, so use of an encryption mechanism is highly recommended for security reasons.