RT: Request Tracker

System Requirements

RT is a web application which works with any modern browser, including many popular mobile devices, and the email interface works with any mail client, from Outlook to Apple Mail to Thunderbird to Gmail. On the server side, RT requires a Unix or Linux operating system, SQL database, web server, and Perl.

Operating system
Linux, Mac OS X server, FreeBSD, Solaris, or another Unix-like operating system
Database
MySQL, PostgreSQL, and Oracle
Web server
Apache, Lighttpd, nginx, or any other server which supports FastCGI