Nmap NSE 6.01: http-open-proxy

Checks if an HTTP proxy is open. The script attempts to connect to www.google.com through the proxy and checks for a valid HTTP response code. Valid HTTP response codes are 200, 301, and 302. If the target is an open proxy, this script causes the target to retrieve a web page from www.google.com. SYNTAX: proxy.url: Url that will be requested to the proxy proxy.pattern: Pattern that will be searched inside the request results