AMaViS (A Mail Virus Scanner) scans e-mail attachments for viruses using third-party virus scanners available for UNIX environments. It resides on a UNIX (Linux) machine and looks through the attached files arriving via e-mail, generates reports when a virus is found and sets the delivery on hold.
getmail is intended as a simple, secure, and reliable replacement for fetchmail. It retrieves email (either all messages, or only unread messages) from one or more POP3, SPDS, or IMAP4 servers (with or without SSL) for one or more email accounts, and reliably delivers into qmail-style Maildirs, mboxrd files, or through external MDAs (command deliveries) specified on a per-account basis. getmail also has excellent support for domain (multidrop) mailboxes, including delivering messages to different users or destinations based on the envelope recipient address.
aggregate takes a list of prefixes in conventional format on stdin, and performs two optimisations to reduce the length of the prefix list. It removes any supplied prefixes which are supurfluous because they are already included in another supplied prefix (e.g., 220.127.116.11/24 would be removed if 18.104.22.168/17 was also supplied), and identifies adjacent prefixes that can be combined under a single, shorter-length prefix (e.g., 22.214.171.124/24 and 126.96.36.199/24 can be combined into the single prefix 188.8.131.52/23).
DataReel is a free, cross-platform database and communications toolkit. It can be used to rapidly develop and deploy multi-threaded database and communications applications. The DataReel toolkit is composed of a modular C++ library designed to build cross-platform infrastructures for end-user applications, embedded systems, and reusable libraries. DataReel's unique modular design simplifies adaptation, allowing you to determine the level of complexity. DataReel makes Internet connectivity and database programming easy.
MailScanner is an email virus scanner, vulnerability protector, and spam tagger. It supports the Postfix, Sendmail, Exim, Qmail, and ZMailer MTAs, and the Sophos, McAfee, F-Prot, F-Secure, CommandAV, InoculateIT, Inoculan, eTrust, Kaspersky, Nod32, AntiVir, BitDefender, RAV, Panda, DrWeb, ClamAV, and other anti-virus scanners. It uses SpamAssassin for highly successful spam identification, and is designed to handle denial of service attacks. It will detect password-protected zip files and apply filename checking to their contents. It is very easy to install, requires no changes at all to your sendmail.cf file, is designed to be lightweight, and won't grind your mail system to a halt with its load. It can be integrated into any email system, regardless of the software in use.
ScannerDaemon is the virus scanner of the OpenAntivirus project. You can send a filename to it via simple TCP and it will scan the file for viruses and tell you if the file is infected or not. The ScannerDaemon comes with its own virus database, so you do not need any commercial virus scanner. There is a plugin for AMaViS and several mailservers to scan all EMail going through a mail server.