The System Logs feature offers a logging utility to the RSFirewall! component, thus empowering the user to keep track of the site security issues.
Essentially it logs all security important events that take place on your Joomla installation. The System Logs tool enables the owner to add various filters like: alert level, date, IP, userID, username and page. Upon pressing on the IP a "Who is" service checks the specified IP address, thus displaying further information.
When clicking on a log event, you will be taken to a page with additional information: several other $_SERVER variables and debugging info (if it's $_GET, $_POST, show the contents).