NoMachine NX is a fast terminal server and desktop virtualization system based on the X11 protocol. NX is an order of magnitude faster than VNC or X11 and can run on bandwidth as narrow as 10 kBit/sec. In addition, NX translates and embeds the MS Windows Terminal Server and VNC protocols into X/NX, enabling users to compress and accelerate remote Windows and VNC sessions. The NX project provides a suite of libraries and X11 proxying agents implementing efficient compression and optimized transport of X11, SMB, IPP, HTTP, and arbitrary protocols like audio and video over the Internet.
The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, Webmail, and mailing list services within a single consistent framework. Individual components can be enabled or disabled at will. Courier implements basic Web-based calendaring and scheduling services integrated in the Webmail module.
MUSCLE (Multi User Server Client Linking Environment) is an N-way messaging server and networking API. It includes client-side networking APIs for various languages, including C, C++, C#, Delphi, Java, and Python. MUSCLE lets programs communicate over a network via streams of serialized Message objects. The included server program ("muscled") lets its clients message each other and store information in its server-side hierarchical database. The database supports flexible queries via hierarchical wildcarding, and "live" updates via a subscription mechanism.
centericq is a text mode menu- and window-driven IM interface that supports the ICQ2000, Yahoo!, AIM, IRC, MSN, Gadu-Gadu, and Jabber protocols. It allows you to send, receive, and forward messages, URLs, SMSes (both through the ICQ server and email gateways supported by Mirabilis), contacts, and email express messages, and it has many other useful features. An internal RSS reader and a LiveJournal client are also provided.
Ekiga (formely known as GnomeMeeting) is a soft phone, video conferencing, and instant messenger application for use over the Internet. It supports HD sound quality and video up to DVD size and quality. It is interoperable with many other standards compliant software, hardware, and service providers as it uses both of the major telephony standards, SIP and H.323.
Mail Avenger is a highly-configurable, MTA-independent SMTP server. It lets users run messages through filters like ClamAV and SpamAssassin during SMTP transactions, so the server can reject unwanted email before assuming responsibility for its delivery. Other unique features include TCP SYN fingerprint and network route recording, SPF (sender policy framework) as a general policy language, qmail-style delivery of extension addresses, validation of sender addresses through SMTP callbacks, mail-bomb protection, integration with kernel firewalls, and more.
GNU Mailutils is a rich and powerful protocol-independent mail framework. It contains a series of useful mail libraries, clients, and servers. These are the primary mail utilities for the GNU system. The central library is capable of handling electronic mail in various mailbox formats and protocols, both local and remote. Specifically, this project contains a POP3 server, an IMAP4 server, and a Sieve mail filter. It also provides a POSIX "mailx" client and a collection of other handy tools.