ClearOS is an integrated network server gateway solution for small and distributed organizations. The software provides all the necessary server tools to run an organization including email, anti-virus, anti-spam, file sharing, groupware, VPN, firewall, intrusion detection/prevention, content filtering, bandwidth management, multi-WAN, and more. You can think of it as a next generation small business server. Through the intuitive Web-based management console, an administrator can configure the server software along with integrated cloud-based services.
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.
XCmail is a MIME and multi POP3 capable mailtool for X11 using the Xclasses X11 layout library. Its main purpose is to read and write mail, allowing any kind of data to be attached. It can handle MIME types, has helpers to show different types, and can encode and decode binary data into ASCII to allow it to be transported as mail over the Internet. It has many built-in functions such as 2 vCards, unlimited POP3 servers, SMTP, SMTP after POP3, SMTP-AUTH (RFC2554), addressbook, encoders, filters, a special spam filter, spell checker, xface, and a new "virtual folder" concept. It also uses external programs to enhance its feature set. XCmail can be extended through a plugin interface.
Clusters and server farms often have many nodes and very little hardware support for locating and diagnosing problems, especially if the problem involves the network interface. Helpme is a small stand-alone program that allows a node to use the standard PC speaker, both to signal that a problem has been detected and to render arbitrary alphanumeric text using either Morse code or the NATO phonetic alphabet. The input syntax allows repeating messages and more.