ProxyJudges are scripts which help you determine the type of a proxy.

They read out HTTP Environment Variables and print them, thus you can see if the proxy you use is transparent (sends your real IP address with every request) or anonymous (does not send your real IP). The use of ProxyJudge scripts is often automatized via Proxy Tools which verify and classify proxies en masse.

While there are different scripts with different HTML outputs, their job is the same: Output HTTP Environment Variables. For proxy servers, the following variables are relevant:

• HTTP_X_FORWARDED_FOR
• HTTP_CLIENT_IP
• HTTP_VIA
• HTTP_FROM
• CLIENT_IP
• REMOTE_ADDR
• REMOTE_HOST

If you want to surf anonymously, neither of these variables should contain your real IP address or host. Additionally, there are certain flags which are tells for a web server that a proxy is being used, eg. HTTP_VIA which could contain proxy information.

The most widely accepted ProxyJudge scripts are:

• ProxyJudge (prxjdg.cgi), 2.34 and 2.35 being the most common ones
• AZ Environment Variables (azenv.php and azenv.pl)
• JEnv by G-Lock Software (jenv.cgi)

Since these are PHP/CGI scripts, you can download them and put them up on a web host if you want to have your own dedicated ProxyJudge. If you require a very fast proxy verification, it makes sense to install your own ProxyJudge because public Judges can be slow or not available sometimes as they run constantly at a high load.
If you choose a certain ProxyJudge script, be sure to check if it is compatible with your Proxy checker. For example, there are some Tools which only support prxjdg.cgi judges for checking proxies.

Here is a list of public proxy judges by type:

ProxyJudge - prxjdg.cgi

• http://shigeru.page.ne.jp/for/prxjdg.cgi
• http://www2.dokidoki.ne.jp/tomocrus/cgi-bin/check/prxjdg.cgi
• http://anonymitytest.com/cgi-bin/prxjdg.cgi
• http://realwork.de/cgi-local/prxjdg.cgi
  
• http://f22.aaa.livedoor.jp/~focean/env/proxyjudge.cgi (banner ad on top, maybe incompatible)
• http://www.proxy4free.info/cgi-bin/prxjdg.cgi
  

AZ Environment Variables - azenv.php/cgi

• http://thecric.free.fr/AZenv/azenv.php

• http://proxy.us.pl/azenv.php
• http://www.proxywordl.hbg.fr/azenv.php
  
• http://www.internetsec.org/azenv.php
• http://www.nassc.com/pr.php