Internet

Adaptive Communication Environment
An Object-Oriented Network Programming Toolkit. (C++) [Many platforms]
http://www.cs.wustl.edu/~schmidt/ACE.html

FarCry
Open-source Content Management System running on ColdFusion MX platform. Support for SQL databases.
http://www.farcrycms.org/

HTun
Linux-based VPN daemon that allows establishment of a full IP-layer link over an HTTP proxy. (C) [Linux]
http://htun.runslinux.net

IP Calculator
Small online utility for IP address calculations including netmask, broadcast and network addresses as well as Cisco wildcard mask. (Perl)
http://jodies.de/ipcalc

Linux Embedded Appliance Firewall (LEAF)
Embedded Linux network appliance for use in small office and home automation environments; can be used as a gateway, router, firewall or in other ways. (C, C++, Shell script) [GNU/Linux]
http://leaf.sourceforge.net/

Lookandfeel Software
Free software for web-based applications, including email components, an NT service for Java applications and small Win32 COM utilities. (Visual C++) [Windows]
http://freesoftware.lookandfeel.com/

Mobilemaps
An open source search and locate engine which allows users to find Web pages by location. (C, Perl) [GNU/Linux, MacOSX, Windows]
http://www.mobilemaps.com

ObjectWeb
Software community aiming to develop component-based middleware for large scale distributed systems.
http://www.objectweb.org/

OpenH323Proxy
Proxy software to allow h.323 applications to pass firewall and NAT. (C++) [Windows 95/98/2000, BSD, Linux]
http://openh323proxy.sourceforge.net

Rimcp
Reboots your hanged machine with a simple ping over network. (C) [GNU/Linux]
http://nail.itapac.net/ricmp/

Shibboleth
Privacy and security aware mailing list project and software. (Perl)
http://shibboleth.sourceforge.net/

Snare Auditing Agents
Tools to retrieve audit and event log information from a variety of operating systems and applications.
http://www.intersectalliance.com/projects/index.html

Spindex
Scripts for searching web sites, both from a client and server perspective. (Perl)
http://mattwork.potsdam.edu/projects/wiki/index.php/Spindex

Zebedee Secure Tunnel
Establishes an encrypted, compressed tunnel for TCP/IP or UDP traffic between two systems. (C) [Unix, Windows 95/98/NT]
http://www.winton.org.uk/zebedee/