1、通过header、端口反扫来识别，见proxyserverprivacy的说明：As you already know Basis proxy detector analyze typical proxy variables that your browser send to the web server, among other things, VIA, PROXY_CONNECTION and X_FOWARDED_FOR and can succesfuly determine of you are behind transparent proxy or anonymous proxy. Elite proxy (Level 1 and Level 2 proxy defined by ProxyJu