Clam AntiVirus is an anti-virus toolkit designed especially for email scanning on mail gateways. It provides a number of utilities, including a flexible and scalable multi-threaded daemon, a commandline scanner, and a tool for automatic database updates. The core of the package is an anti-virus engine available as a shared library.
John the Ripper is a fast password cracker, currently available for many flavors of Unix, Windows, DOS, BeOS, and OpenVMS. Its primary purpose is to detect weak Unix passwords. It supports several crypt(3) password hash types commonly found on Unix systems, as well as Windows LM hashes. On top of this, lots of other hashes and ciphers are added in the community-enhanced version (-jumbo), and some are added in John the Ripper Pro.
Socat is a relay for bidirectional data transfer between two independent data channels. Each of these data channels may be a file, pipe, device (terminal or modem, etc.), socket (Unix, IP4, IP6 - raw, UDP, TCP), SSL, a client for SOCKS4, or proxy CONNECT. It supports broadcasts and multicasts, abstract Unix sockets, Linux tun/tap, GNU readline, and PTYs. It provides forking, logging, and dumping and different modes for interprocess communication. Many options are available for tuning socat and its channels. Socat can be used, for example, as a TCP relay (one-shot or daemon), as a daemon-based socksifier, as a shell interface to Unix sockets, as an IP6 relay, or for redirecting TCP-oriented programs to a serial line.
di is a disk information utility that displays everything that df does and more. It features the ability to display your disk usage in whatever format you prefer. It also checks the user and group quotas, so that the user sees the space available for their use, not the system wide disk space. It is designed to be highly portable across many platforms and is great for heterogenous networks.
Firewall Builder consists of a GUI and set of policy compilers for various firewall platforms. It helps users maintain a database of objects and allows policy editing using simple drag-and-drop operations. The GUI and policy compilers are completely independent, which provides for a consistent abstract model and the same GUI for different firewall platforms. It currently supports iptables, ipfilter, ipfw, OpenBSD pf, Cisco PIX and FWSM, and Cisco routers access lists.