NetPlug is an extensible multi-connections, multi-protocol, network client program, written in pure Tcl/Tk. Includes a complete Irc client plug in that you should love if you like IrcII 'classic' look & feel (plus customizable style/colors scheme, sound,... Now includes full DCC support (with GUI), ircII like aliases and improved scripting (Tcl!), keywords (your nick...) highlighting, and more
Dialback is a set of html pages and some bash scripts to enable a host to call you back and set up a ppp link. It also includes a MS Windows dial-up networking script should you wish to use such a machine for a client. It is intended for legitimate remote access where you need good security (ppp link only available on return call) and/or the other end is willing to foot the bill for your connection time. Please note that it should be fairly to set up other protocols such as slip.
kipmp is an IPMP-like daemon that will flip a server's IP address between a primary and backup network interface based on the result of active probes against a (hopefully redundant) target like a default gateway. It is useful when one server is connected to multiple switches in the same network and higher availability is desired.
Argus is a system and network monitoring application. It will monitor nearly anything you ask it to monitor (TCP + UDP applications, IP connectivity, SNMP OIDS, etc). It presents a clean, easy-to-view Web interface. It can send alerts numerous ways (such as via pager) and can automatically escalate if someone falls asleep.
pv (Pipe Viewer) is a terminal-based tool for monitoring the progress of data through a pipeline. It can be inserted into any normal pipeline between two processes to give a visual indication of how quickly data is passing through, how long it has taken, how near to completion it is, and an estimate of how long it will be until completion.
BW whois is a modern whois client that works as a full-featured Web application or as a commandline tool. It is flexible and configurable with self-detecting CGI support, multiple security options in the CGI mode, a mature TLD table, database caching (using MySQL or PostgreSQL), and many more options and features.
Spong is a simple system-monitoring package. It features client-based monitoring (CPU, disk, processes, logs, etc.), monitoring of network services, grouping of hosts (routers, servers, workstations, and PCs), host-specific contact and downtime information, configuration on a client-by-client basis, results displayed via the Web, history of problems, messaging (via email or pager) when problems occur, and verbose information to help diagnosis problems. It communicates via simple TCP-based messages, and is written in Perl.
Report Magic is an add-on for Analog, a Web site logfile analysis program. Generated reports include a description with tabulated, graphed, and summarized results. All colors, fonts, and background images are completely customizable to help make resulting reports fit the theme of your Web site. Report Magic has translations for several languages. It runs on any platform that will run Perl and pre-compiled versions are available for Win32 and Mac.