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.
Anteater is a log analyser for MTA logfiles (such as those produced by sendmail and postfix). The tool is written in 100% C++ and is very easy to customize. Input, output, and the analysis are modular class objects with a clear interface. Currently, there are modules for reading the syslog format of sendmail and postfix that do up to eight useful analyses and write the result in plain ASCII or HTML, to stdout or to files.
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.
KBiff is a KDE "biff" or new mail notification utility. It is highly configurable but very easy to use and setup. It supports session managment (it "remembers" the last state it was in before you logged off) and can be docked into the panel. It has support for mbox (Unix-style), maildir (qmail-style), mh, POP3, IMAP4, and NNTP mailboxes.
RFC Util allows you to specify the number of an RFC, or a search string, and it returns all related RFCs. It features command line switches to spawn lynx or w3m to view the RFC, dump to file for offline viewing, or mail to an address. It also allows local and remote lookups of port, service, or proto numbers.
Smail is a Mail Transport Agent. Its job is to accept mail messages from sources on the local machine, or from remote hosts, and deliver those messages to the appropriate destinations, be they to remote hosts or to files or programs on the local machine. Smail is designed to be mostly compatible with sendmail but uses a much simpler configuration scheme.
Lire is a pluggable log analyzer. It has analyzers for over 25 log file formats, ranging from Apache WWW log files to iptables firewall logs and CUPS printing logs. Reports are generated in 9 different output formats, ranging from Excel 95 to PDF to HTML, optionally with included graphs.