Get the Real Client IP Address

Walk common proxy headers and REMOTE_ADDR, then return the first public IP that is not private or reserved, or Unknown if none validate.

Language: PHP

Added on: 19^th August 2026

Submitted by: Lupraxus

function get_real_ip()
{
    foreach (array('HTTP_CLIENT_IP', 'HTTP_X_FORWARDED_FOR', 'HTTP_X_FORWARDED', 'HTTP_X_CLUSTER_CLIENT_IP', 'HTTP_FORWARDED_FOR', 'HTTP_FORWARDED', 'REMOTE_ADDR') as $key) {
        if (array_key_exists($key, $_SERVER) === true) {
            foreach (explode(',', $_SERVER[$key]) as $ip) {
                $ip = trim($ip);

                if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) !== false) {
                    return $ip;
                }
            }
        }
    }
    return 'Unknown';
}

Caveats

Forwarded headers can be spoofed. Private and reserved addresses are skipped, so local or LAN clients often return Unknown.