I wrote .htaccess code for blocking proxy server. If you want to block proxy server using .htaccess than just write below code in .htaccess file and you rocks.
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]
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