CAKE (Key Addressed Crypto Encapsulation) is a bunch of Python and C++ for implementing the CAKE protocol. The CAKE protocol is a protocol in which all messages have source and destination addresses that are public keys. This is in the same way that IP packets have a source and destination address that is an IP address.
DJIGZO Email Encryption Gateway is a centrally managed email server that encrypts and decrypts incoming and outgoing email at the gateway level. Djigzo currently supports two encryption standards: S/MIME and PDF encryption. The built-in Data Leak Prevention (DLP) module can be used to prevent certain information from leaving the organization via email. DLP can be configured to filter on credit card numbers, bank account numbers, excessive amounts of email addresses or other personal information in one email message, and more. DJIGZO can be installed on most Linux and Unix based systems. Installation packages are available for Ubuntu, Debian, Red Hat and CentOS. A ready to run virtual appliance for VMware and Hyper-V is available. An add-on for BlackBerry is available.
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.
SPF is a new strategy for preventing junk mail. The present SMTP standard for email allows anyone to forge anyone else's email address. SPF verifies that the Sender address of an email message matches (according to some policy) the client IP address that submitted it. libspf2 is a complete and robust implementation of SPF which provides support for many MTAs. Support for new MTAs is in progress.
vthrottle is an implementation of an SMTP throttling engine for Sendmail servers, based upon M. Williamson's mechanisms, as described in his 2003 Usenix Security paper. It allows the administrator to control how much email users and hosts may send, hindering the rapid spread of viruses, worms, and spam. Exceptions can be made using a whitelist mechanism, which can be generated manually or with the included tool "vmeasure". vthrottle tells the misbehaving client to hold on to the deferred mail and resend it at a later time.
BitDefender Mail Protection is a powerful mail filtering solution that provides antivirus and antispam capabilities to Linux mail servers. Both sent and received messages are scanned in real-time, avoiding possible infections and preventing anyone from sending an infected message. It claims a 100% detection rate for all viruses in the wild through its powerful scanning engines, which are certified by prestigious testing labs.
Sendmail-TLS is a wrapper for Sendmail which allows for clients to make a secure (SSL) connection to their mailserver as described in RFC 2487. The connection is internally forwarded to sendmail and does not require sendmail to be running on port 25. Clients which support this currently are Netscape Messenger, Microsoft Outlook, and Microsoft Outlook Express.
smtpfilter is a filter for an SMTP session which passes the session through transparently in real time, except for the DATA command which is intercepted in order to scan the data for spam and/or viruses with the scanner of your choice. The sources are heavily commented. The default spam filtering is a hybrid approach that uses spamassassin to self-train the excellent spamprobe Bayesian filter which works on a per-site rather than per-user basis. The virus checking can use clamav or NAI, or any other command- line scanner.