A free and reliable P2P BitTorrent client
An advanced and multi-platform BitTorrent client with a nice Qt user interface as well as a Web UI for remote control and an integrated search engine. qBittorrent aims to meet the needs of most users while using as little CPU and memory as possible.
A free peer-to-peer (P2P) file sharing client
eMule is a free peer-to-peer (P2P) file-sharing client for Microsoft Windows that was launched in 2002 as an alternative to eDonkey2000. To date, eMule is one of the world’s largest and most trustworthy P2P file-sharing clients. eMule includes advanced search features, file checks for corruptions while downloading, a preview while downloading function, and a credit system to reward frequent uploads.
An extremely powerful and configurable BitTorrent client
Vuze (formerly Azureus) is an extremely powerful and configurable BitTorrent client. Search and download torrent files. Play, convert and transcode videos and music for playing on many devices such as PSP, TiVo, XBox, PS3, iTunes (iPhone, iPod, Apple TV).
A universal P2P file sharing client for Windows
Shareaza is a very powerful multi-network peer-to-peer file-sharing client supporting Gnutella² G2, Gnutella, eDonkey2000 / eMule, DC++, HTTP, FTP and BitTorrent / DHT protocols for Windows or Wine.
A universal instant messaging (IM) program
See https://pidgin.im/about/ for more information. Pidgin is an instant messaging program which lets you log in to accounts on multiple chat networks simultaneously. It runs on Windows, Linux, and other UNIX operating systems. Pidgin is compatible with the following chat networks out of the box: AIM, ICQ, Google Talk, Jabber/XMPP, MSN Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, MXit, Novell GroupWise Messenger, Lotus Sametime, SILC, SIMPLE, MySpaceIM, and Zephyr. It is written in C and makes heavy use of GLib and GTK+. Finch is a command line instant messaging program. It also lets you log in to accounts on multiple chat network simultaneously, and it is compatible with the same chat networks as Pidgin. It is written in C and makes heavy use of GLib and ncurses.
Free and open source webmail software
MRBS is a system for multi-site booking of meeting rooms. Rooms are grouped by building/area and shown in a side-by-side view. Although the goal was initially to book rooms, MRBS can also be used to book any resource; computers, planes, whatever you want
Open Source Enterprise Content Management
Alfresco is an open source enterprise content management repository (CMS) built by a team that includes the co-founder of Documentum. Its modular architecture uses the latest open src Java technologies. Includes Document Management, Records Managemen
phpFreeChat is a free, simple to install, fast and customizable chat that uses by default files for message and nickname storage. It uses AJAX to smoothly refresh and display the chat zone and the nickname zone.
A GTK+ Gnutella client, optimized for speed and scalability
A GTK+ Gnutella client, efficient, reliable and fast, written in C. It has been optimized for speed and scalability, with low-memory consumption. It is meant to be left running 24x7, using little CPU and only the configured bandwidth. It is possible to run gtk-gnutella without a GUI or using a shell interface.
Cross-platform player and audio manager
aTunes is a powerful, full-featured, cross-platform player and manager, with support for online radios, podcasts and CD ripping.
Simple, web-based address & phone book
Simple, web-based address & phone book, contact manager, organizer. Groups, addresses, e-Mails, phone numbers & birthdays. vCards, LDIF, Excel, iPhone, Gmail & Google-Maps supported. PHP / MySQL based. http://php-addressbook.sourceforge.net/demo
Multiuser HylaFAX PHP/MySQL Web interface for viewing faxes online, downloading & emailing in PDF format, and categorizing & archiving all sent and received faxes.
phpMyChat-Plus is an easy-to-install, easy-to-use multi-room PHP/DB chat. It is currently available for MySQLi, MariaDB, PostgreSQL, and ODBC. It supports IRC-like commands, moderators, is available in 24 languages and fully compatible with php7.
Owl is a multi user document repository (knowledgebase) , document manager and/or document management system (DMS) written in PHP for publishing of files/documents onto the web for a corporation, small business, group of people, or just for yourself. Final Code Hosted on GitHub
Fully customizable web chat created using AJAX.
NOCC is a simple and fast Webmail client which can handle POP3, SMTP, and IMAP servers. It is written with PHP5 (uses sessions), has low requirements (no database, frames). Features multi-language support, MIME attachments, displays HTML messages.
A multi-protocol instant messaging app for Mac OS X
Adium is an Open Source, multi-protocol instant messaging application for Mac OS X. Adium supports AIM, ICQ, Jabber, MSN, Yahoo!, Google Talk, Bonjour, Gadu-Gadu, Novell Groupwise, SIP/SIMPLE (Text), and Lotus Sametime. Additionally, it supports all of these applications at once so, even if you have multiple IM accounts, you don't have to log into each account separately.
QmailAdmin is a web interface for managing email addresses in virtual domains created by Vpopmail.
FUDforum is a super fast and scalable discussion forum. It is highly customizable and supports unlimited members, forums, posts, topics, polls & attachments. It can import XML Feeds and sync with USENET groups and Mailing Lists (bi-directional).
Thunderbird-Tray is a system tray launcher tool for Mozilla Thunderbird, the popular e-mail client. You can use TB-Tray to hide Thunderbird to the tray while you don't need it. When you click the tray icon, TB-Tray will restore Thunderbird.
AfterLogic WebMail Lite PHP is a free AJAX webmail application. Users can receive, view, manage, compose, and send email through web interface (IMAP and SMTP supported). Source code included.
Diverse P2P Filesharing
PeerProject is a versatile peer-to-peer filesharing client and file manager. Intuitive and aesthetic while supporting many networks and features. BitTorrent, G2, Gnutella, eDonkey, DC++, IRC, http/ftp & more. Mainstream fork of Shareaza p2p, for Windows & WINE. (See Envy fork for further development.)
mvnForum is a open source, powerful, easy to use/setup bulletin board (forum) built on the J2EE technology(Jsp/Servlet) and compatible with any Servlet Container which supports Jsp 1.2 and Servlet 2.3. The official home page is www.mvnForum.com
Simple, modern & fast web-based email client
Modest system requirements, decent performance, simple installation and upgrade, no database required - all these make RainLoop Webmail a perfect choice for your email solution.