Apache Web Server (1.x or 2.x)
Apache is primarily used to serve both static content and dynamic Web pages on the World Wide Web. Many web applications are designed expecting the environment and features that Apache provides.
MySQL Database (3.23.49 or above)
MySQL is a relational database management system (RDBMS) which has more than 11 million installations. The program runs as a server providing multi-user access to a number of databases.
PHP (5.2.17 or below)
PHP is a scripting language originally designed for producing dynamic web pages. It has evolved to include a command line interface capability and can be used in standalone graphical applications.
A tool to protect software written using the PHP programming language from being viewed, changed, and run on unlicensed computers.
Crontab or Scheduled Task
cron is a time-based scheduling service in Unix-like computer operating systems. 'cron' is short for 'chronograph'.
Optional: PHP as apache module if you need htaccess or htpasswd supported. cURL is also required if you use authorize.net payment gateway.