The Killabot APx System has been designed to detect certain characteristics common amongst anonymizing proxies. Their signatures are sometimes hard to detect but there is an algoritm that can return results with a very high degree of accuracy.

This Plugin is a web service, inspecting incoming web requests [form submissions] and detects anonymizer proxy usage that could negatively affect a web server’s performance or security.

The plugin can be downloaded here: Killabot APx Plugin download