iptables is built on top of netfilter, the packet alteration framework for Linux 2.4.x and 2.6.x. It is a major rewrite of its predecessor ipchains, and is used to control packet filtering, Network Address Translation (masquerading, portforwarding, transparent proxying), and special effects such as packet mangling.
isdn4net is a collection of scripts and configuration files to help you run isdn4linux. It is designed for fast setup of a simple dialout to one ISP, but may also be used for management of complex setups. It is intended for Mandrake systems, but if there is interest, it could be adapted to others as well.
iSSL (independant Secure Sockets Layer) is a minimalistic cryptographical API that uses the RSA and AES ciphers to establish SSL-alike, secure encrypted communications between two peers communicating through a network socket, including session key generation and public key exchange.
The Jasmin software distribution includes an implementation of the Script MIB according to RFC 2592 with a Java runtime engine, a selection of demonstration scripts, a Java package called "scriptmib" supporting the development of manager applications for the Script MIB, Smurf, a graphical user interface to the Script MIB, and JAX, a Java package for building AgentX sub-agents.
JFwadmin is a Java 2 high-level X11 tool for ipchains. The GUI displays easy-to-understand services. Features include scripts generation, firewall save and restore, automatic interface and IP address and routes detection, current firewall configuration display, and handling of masq-modules and port-forwarding.
joyd is a very flexible program that allows you to execute commands via a joystick or joypad attached to your computer. One simple possibility would be to reboot when your keyboard is hung. It can use any device supported by the Linux Joystick Driver. Helper applications allow you to test the joystick status in your own shell scripts.