Due to prevention of double post, “HTTP_X_FORWARDED_FOR” and “REMOTE_ADDR” are two related variables for checking client IP address. As you know HTTP_X_FORWARDED_FOR is used in case of client reach the server via “Web Proxy”.

Unfortunately, HTTP_X_FORWARDED_FOR is unreliable variable because of easy to spoof!

Please give me some suggestion how I check double post.

PS. You guys can show me into source code PHP, ASP, Perl, Phyton whatever.

Thanks
Tony