Bugzilla is the leading open-source/free software bug tracking system, with high-profile installations at mozilla.org, GNOME, Red Hat, and NASA, among others. It features a comprehensive set of fields, attachment management, inter-bug dependencies, email notification of changes, a powerful query interface, reporting, and Web, XML, email, and console interfaces. It can be managed entirely using a Web-based UI. The user UI is customizable using templates.
RT is an industrial-grade trouble ticketing system. It lets a group of people intelligently and efficiently manage requests submitted by a community of users. RT is used by systems administrators, customer support staffs, NOCs, developers, and even marketing departments to track issues, outages, bugs, requests, and all kinds of other things at thousands of sites around the world.
TWiki is a flexible, powerful, and simple Web based collaboration platform. It is suitable for dynamic intranets and knowledge bases, and for sharing and managing documents and collaborative projects. It resembles a normal Web site, but every page can be changed from a browser. It features automatic link generation, full text search, group authorization, Web forms, reporting, change notification, file attachments, revision control of pages and attachments, a modular templating system with skins, hierarchical navigation based on the topic parenting feature, and more. Plugins can be used to enhance the program and build groupware applications.
The Apache Open For Business Project is an enterprise automation software project that includes ERP, CRM, E-Business/E-Commerce, SCM, MRP, and CMMS/EAM functions. It is a foundation and starting point for enterprise solutions and can certainly be used out of the box, but is also great for creating specialized applications.
PHP Trouble Ticket provides a centralized means of problem reporting and tracking in multi-user environments (medium to large companies, development groups, etc.). It helps direct problem reports to the responsible administrator(s), keeps track of the status of a problem being worked on, and offers an up-to-date list of recent changes applied. It aims to be widely configurable, easy-to-use even for those not technically inclined, and multi-language capable.
BATTS (Barnhard Associates Trouble Ticketing System) is a lean, elegant trouble ticket system with both command line and Web interfaces, written in Perl. It uses MySQL for its backend, and has a ticket-via-email interface for submission and informational logging. Features include support for tickets pending on or resolved when other tickets are disposed of, an ability to assign tickets to a person, an ability to categorize and prioritize tickets, and associating billing codes with various logging events.
OTRS is a platform independent Web-based help desk system that supports service organization of any kind (e.g. IT service, customer and technical product service, complaint management, public services, etc.) to increase their efficiency. It increases transparency as well as service quality and lowers your total cost of ownership. It has been certified ITIL V3 compatible by PinkVERIFY for incident, problem, change, service asset and configuration, request fulfillment, and knowledge management. Other ITIL processes like service catalog and service level management are supported as well.
ITracker is a Java J2EE issue/bug tracking system designed to support multiple projects with independent user bases. It supports features such as full i18n support, multiple versions and project components, detailed histories, issue searching, file attachments, dynamic reports with charts, configurable field values, customizable project level fields, pluggable authentication, a built-in scheduler, and email notifications.