A better way to block proxy servers

Rather than attempt to block proxy servers by who they are (i.e., via their specified domain identity), it is far more expedient and effective to block proxy servers by what they do. By simply blacklisting the various HTTP protocols employed by proxy servers, it is possible to block virtually all proxy connections. Here is the code that I use for stopping 99% of the proxies that attempt to access certain sites:

# block proxy servers from site access
# http://perishablepress.com/press/2008/04/20/how-to-block-proxy-servers-via-htaccess/

RewriteEngine on
RewriteCond %{HTTP:VIA}                 !^$ [OR]
RewriteCond %{HTTP:FORWARDED}           !^$ [OR]
RewriteCond %{HTTP:USERAGENT_VIA}       !^$ [OR]
RewriteCond %{HTTP:X_FORWARDED_FOR}     !^$ [OR]
RewriteCond %{HTTP:PROXY_CONNECTION}    !^$ [OR]
RewriteCond %{HTTP:XPROXY_CONNECTION}   !^$ [OR]
RewriteCond %{HTTP:HTTP_PC_REMOTE_ADDR} !^$ [OR]
RewriteCond %{HTTP:HTTP_CLIENT_IP}      !^$
RewriteRule ^(.*)$ - [F]

To use this code, copy & paste into your site’s root htaccess file. Upload to your server, and test it’s effectiveness via the proxy service(s) of your choice. It may not be perfect, but compared to blacklisting a million proxy domains, it’s lightweight, concise, and very effective ;)