The Eclipse PDT has two types of debugging capabilities:
Internal – For local debugging. It uses a local copy of PHP 4 or PHP 5.
Server - For debugging remote servers that are accessed online from the Client application. When debugging files on a remote server the debugger uses the PHP installed on the remote server.
The internal debugger is a suite of debugging tools that allows the developer to debug applications as they are being developed-before they are uploaded to the web server.
To set the configurable debug options go to: Windows | Preferences | Debug.
These settings can be configured to suit your requirements.
Many of these settings were setup during the installation process.