a multi-purpose application level gateway, or a proxy server which runs on multiple platforms (Unix, Windows, MacOS X and OS/2). DeleGate mediates communication of various protocols (HTTP, FTP, NNTP, SMTP, POP, Telnet, SOCKS, etc.)
a discrete event simulator targeted at networking research. Ns provides substantial support for simulation of TCP, routing, and multicast protocols over wired and wireless (local and satellite) networks
aims to be a secure IM for multiple platforms. Keep in touch is an attempt to create a secure instant messenger - it supports its own XML based protocol aswell as ICQ and AIM
a modular, plugin-driven peer-to-peer client framework which is designed with true multi-network downloads in mind. It can be used directly via the built-in shell functionality, or via external user interfaces.
a free multiplayer online game with 3d graphics. Become part of an epic adventure in an ever-growing universe, complete with high-tech quests, enemy factions, and explosive space battles.
port of the X Window System server to Windows. It shares the same source code base as Cygwin/X, but does not depend on the Cygwin environment or cygwin1.dll. Xming is a fully featured X11 server for Windows that is very simple to install and use.