Lighttpd

Lighttpd should have a feature where the admin can set the maximum incoming/outgoing bandwidth(http/https/ftp, etc) that Lighttpd can use per month(30 days). The admin can choose what will happen when Lighttpd reaches the monthly bandwidth limit, like to display a "bandwidth exceeded" page OR an option to automatically shutdown the CentOS/Ubuntu/etc server.
The date/time can be retrieved from the CentOS/Ubuntu/etc clock, so the admin can choose what date/time the month starts at. There should be an option to keep the monthly bandwidth logs on the server.

So for example, if a person chooses a 10000GB(10TB) monthly bandwidth limit, Lighttpd will either display a 'bandwidth exceeded' html page OR shutdown the server(whatever the admin chooses) when the bandwidth limit is reached.