ntop : A network probe that shows network usage in a way similar to what top does for processes

ntop is a network probe that shows network usage in a way similar to what top does for processes. It acts as a Web server, creating an HTML dump of the network status. It sports a NetFlow/sFlow emitter/collector, an HTTP-based client interface for creating ntop-centric monitoring applications, and RRD for persistently storing traffic statistics.

• Licenses : GPL
• Operating Systems : Windows, POSIX, Linux

gscan2pdf : A GUI to ease the process of producing PDFs from scanned documents

gscan2pdf is a GUI to ease the process of producing PDFs from scanned documents. You scan in one or several pages and create a PDF of selected pages. Scanning is handled with SANE via scanimage. PDF conversion is done by PDF::API2. Perl is used for portability and ease of programming, with gtk2-perl for the GUI.

• Licenses : GPL
• Operating Systems : POSIX
• Implementation : Perl

Dkopp : A program for copying or backing up disk files to DVD or BD (Blu-ray)

Dkopp is a program for copying or backing up disk files to DVD or BD (Blu-ray). Full or incremental backups can be made, with full or incremental media verification. Dkopp uses a GUI to navigate through directories to select or de-select files or directories at any level. Backup jobs can be saved for recurring use. New, deleted, and updated files are handled automatically, without re-editing the backup job. An incremental backup updates the same media used for a prior full backup. A GUI restore function is also provided. Differences between disk and DVD/BD can be reported in total, by directory and by file.

• Licenses : GPLv3
• Operating Systems : Linux
• Implementation : C++

FreeRADIUS : A high-performance, highly configurable, and feature-rich RADIUS server

FreeRADIUS is a high-performance, highly configurable, and feature-rich RADIUS server. Supported features include EAP (wireless authentication, PEAP, TTLS), MySQL, PostgreSQL, Oracle, LDAP, X9.9 token cards, VMPS, and many more. It comes with more than 50 vendor dictionaries, and interoperates with many others. It is the only open source RADIUS server that has implemented EAP, and it is currently deployed in multiple million-user systems.

• Licenses : GPL
• Operating Systems : POSIX, Windows, Cygwin, Unix
• Implementation : C

Likewise Open : joins Linux, Unix, & Mac OS machines to Microsoft Active Directory and securely authenticates users with their domain credentiials

Likewise Open is an application that joins Linux, Unix, and Mac OS machines to Microsoft Active Directory and securely authenticates users with their domain credentials. Features include: joining non-Windows systems to Active Directory domains in a single step from the command line or from a GUI; authenticating users with a single user name and password; enforcing the same password policies for all platforms; supporting multiple forests with one-way and two-way cross forest trusts; caching credentials in case your domain controller goes down; and providing single sign-on for SSH and Putty. It does not require Active Directory schema changes for installation.

• Licenses : GPL, GPLv2
• Operating Systems : Mac OS X, Windows, Unix

Instantbird : A multi-protocol instant messaging client

Instantbird is a multi-protocol instant messaging client. Using it, you can connect to all your different IM accounts. It uses the Mozilla rendering engine to display messages, and uses the Pidgin libpurple to connect to the different networks.

• Implementation : C++

RRDtool : The OpenSource industry standard, high performance data logging and graphing system for time series data

RRDtool is the OpenSource industry standard, high performance data logging and graphing system for time series data. Use it to write your custom monitoring shell scripts or create whole applications using its Perl, Python, Ruby, TCL or PHP bindings.

GNU SIP Witch : A secure peer-to-peer VoIP server

GNU SIP Witch is a secure peer-to-peer VoIP server. Calls can be made even behind NAT firewalls, and without requiring service providers. SIP Witch can be used on the desktop to create bottom-up secure calling networks and as a free software alternative to Skype. It can also be used as a stand-alone SIP-based office telephone server, or to create secure VoIP networks for an existing IP-PBX such as Asterisk, FreeSWITCH, or Yate.

• Licenses : GPLv3
• Operating Systems : OS Independent
• Implementation : C++

check_ssl_cert : A Nagios plugin to check X.509 certificates

check_ssl_cert is a Nagios plugin to check X.509 certificates. It checks if the server is running and delivers a valid certificate. It also checks if the CA matches a given pattern, and checks the validity.

• Licenses : GPLv2
• Operating Systems : Mac OS X, Unix
• Implementation : Unix Shell, bash

zlib : Designed to be a free, general-purpose, legally unencumbered, lossless data-compression library for use on virtually any computer hardware

zlib is designed to be a free, general-purpose, legally unencumbered, lossless data-compression library for use on virtually any computer hardware and operating system. The zlib data format is itself portable across platforms. Unlike the LZW compression method used in Unix compress(1), the compression method currently used in zlib essentially never expands the data. (LZW can double or triple the file size in extreme cases.) zlib's memory footprint is also independent of the input data and can be reduced, if necessary, at some cost in compression.

• Licenses : zlib/libpng
• Operating Systems : OS Independent
• Implementation : C

Mausezahn : A fast traffic generator which allows you to send nearly every possible and impossible packet

Mausezahn is a fast traffic generator which allows you to send nearly every possible and impossible packet. Mausezahn can be used, for example, as a traffic generator to stress multicast networks, for penetration testing of firewalls and IDS, for simulating DoS attacks on networks, to find bugs in network software or appliances, for reconnaissance attacks using ping sweeps and port scans, or to test network behavior under strange circumstances. Mausezahn gives you full control over the network interface card and allows you to send any byte stream you want (even violating Ethernet rules).

• Operating Systems : POSIX Linux
• Implementation : C

ip2clue provides access to multiple databases to retrieve country information associated with IP addresses

ip2clue provides access to multiple databases (Maxmind, Software 77, Webhosting.info and ip2location) to retrieve country information associated with IP addresses. It has a daemon that supports lots of concurrent connections and a client binary. Some client examples are also provided in languages including PHP and C.

• Licenses : GPLv3
• Operating Systems : Linux
• Implementation : C, PHP

MultiVNC : A cross-platform, Multicast-enabled VNC viewer

MultiVNC is a cross-platform, Multicast-enabled VNC viewer. Features include support for most encodings, ZeroConf service discovery, a seamless edge control mode á la x2vnc, and most prominently, experimental support for VNC via multicast.

• Licenses : GPLv2
• Operating Systems : Unix, Linux, Windows, Mac OS X
• Implementation : C++, libvncclient, wxWidgets

Spicebird : An email and messaging software

Spicebird is an email and messaging software. It provides email, calendaring, and instant messaging and can connect to any standards based server. It is built with an innovative tabbed user interface and high end functionality.

• Licenses : GPL
• Operating Systems : Windows, POSIX, Linux

Automatic Drawing Generation : GObject-based library

Automatic Drawing Generation is GObject-based library that provides a non-interactive Cairo canvas specifically designed for generating technical drawings.

• Licenses : LGPL
• Operating Systems : Mac OS X, Windows, Linux, Unix, FreeBSD, OpenSolaris
• Implementation : C

WhatWeb fingerprints Web servers and Web applications

WhatWeb fingerprints Web servers and Web applications. It can identify content management systems (CMS), Web application frameworks, default pages for Web servers, blogs, JavaScript libraries, and more. Each time you visit a Web site in your browser, the Web server leaks many hints about the software delivering the Web page. WhatWeb recognizes these hints and reports what it finds. WhatWeb has over 70 plugins. Plugins can identify systems with obvious signs removed by looking for subtle clues. Plugins are flexible and can return any datatype. For example, plugins can return version numbers, email addresses, account IDs, and more.

• Licenses : GPLv2
• Operating Systems : Linux
• Implementation : Ruby

BitlBee allows users to talk to people on the MSN, ICQ, Jabber, Yahoo!, and AIM networks with any IRC client by emulating an IRC server

BitlBee allows users to talk to people on the MSN, ICQ, Jabber, Yahoo!, and AIM networks with any IRC client by emulating an IRC server. A virtual channel is created with all of the user's buddies in it, who can be talked to in the channel or in a query. Also, one can participate in group chats and chat rooms like they were normal IRC channels.

• Licenses : GPL
• Operating Systems : POSIX, Linux, Solaris, BSD, Windows, Mac OS X
• Implementation : C

FreeDiams : A program for making prescriptions of pharmaceutical drugs and testing their interaction

FreeDiams is a program for making prescriptions of pharmaceutical drugs and testing their interactions. It is the result of building the FreeMedForms prescriber plugins into a standalone application. It is developed by medical doctors and is intended for use by these same professionals. It can be used to prescribe drugs and test drug interactions within a prescription. It can be linked to any application by way of its command line parameters. FreeDiams can use several drugs database, including the FDA_USA drug database, the French AFSSAPS drug database, and the Canadian drug databases.

• Licenses : BSD Revised
• Operating Systems : Linux, Mac OS, Windows, FreeBSD
• Implementation : SQLite 3, C++, Qt

Linphone : An audio and video Internet phone with GTK+ and console interfaces

Linphone is an audio and video Internet phone with GTK+ and console interfaces. It uses the SIP protocol, and is compatible with most SIP clients and gateways. It can use various audio and video codecs such as Speex, GSM, G711, ilbc, amr, Theora, H263-1998, MPEG4, H264, and snow.

• Licenses : GPL
• Operating Systems : POSIX, Linux, BSD, FreeBSD, Windows, Mac OS X, iPhoneOS, Android
• Implementation : C

Gearman provides a generic application framework to farm out work to other machines or processes that are better suited to do the work

Gearman provides a generic application framework to farm out work to other machines or processes that are better suited to do the work. It allows you to do work in parallel, to load balance processing, and to call functions between languages. It can be used in a variety of applications, from high-availability web sites to the transport of database replication events. In other words, it is the nervous system for how distributed processing communicates. A few strong points about Gearman:

• Open Source - It's free! (in both meanings of the word) Gearman has an active open source community that is easy to get involved with if you need help or want to contribute.
• Multi-language - There are interfaces for a number of languages, and this list is growing. You also have the option to write heterogeneous applications with clients submitting work in one language and workers performing that work in another.
• Flexible - You are not tied to any specific design pattern. You can quickly put together distributed applications using any model you choose, one of those options being Map/Reduce.
• Fast - Gearman has a simple protocol and interface with a new optimized server in C to minimize your application overhead.
• Embeddable - Since Gearman is fast and lightweight, it is great for applications of all sizes. It is also easy to introduce into existing applications with minimal overhead.
• No single point of failure - Gearman can not only help scale systems, but can do it in a fault tolerant way.

libmemcached : A C client library for interfacing to a memcached server

libmemcached is a C client library for interfacing to a memcached server. It has been designed to be light on memory usage, thread safe and to provide full access to server side methods. It also implements several command line tools: memcat, memflush, memrm, memstat, and memslap (for load generation). The library has been designed to allow for different hashing methods on keys, partitioning by keys, and to use consistent hashing for distribution.

• Licenses : BSD Revised
• Operating Systems : POSIX
• Implementation : C, C++

IPFire : A Linux firewall distribution that is built from source and comes with lots of additional features

IPFire is a Linux firewall distribution that is built from source and comes with lots of additional features. It is easy to set up and administer. It features a firewall with stateful inspection, a content filtering engine, traffic control (QoS), VPN technology, and a lot of logging.

• Licenses : GPLv3
• Operating Systems : POSIX, Linux

Cuneiform : A commercial grade optical character recognition (OCR) system

Cuneiform is a commercial grade optical character recognition (OCR) system. It was originally developed and open sourced by Cognitive technologies, and was originally Windows-only. This project aims to port Cuneiform to run natively on Linux.

• Licenses : BSD Revised
• Operating Systems : Windows, Mac OS X, POSIX, Linux
• Implementation : C, C++