block - Avoid people from entering my site using anonymous proxy -

avoid people entering site using anonymous proxy. possible? have wannabe hacker trying enter joomla site. joomla site has plugin warns me email every login attempt , shows me ip of computer trying enter. ip different every 5 or attempts.

check similar topic joomla forum http://forum.joomla.org/viewtopic.php?f=267&t=295854

in short suggests is

if(isset($_server['http_x_forwarded_for']) || ($_server['http_user_agent']=='') || ($_server['http_via']!='')){         die(" "); 

this code put in index.php under joomla root, right after line define( '_valid_mos', 1 );

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you see more information on topic in article http://www.wikihow.com/block-proxy-servers

in last one, there suggested following .htaccess rule

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] 

which adds several more headers compared first approach suggested in joomla forum topic.