How can the function getIP() be used to accurately retrieve IP addresses in PHP instead of relying solely on $_SERVER['REMOTE_ADDR']?

The issue with relying solely on $_SERVER['REMOTE_ADDR'] is that it can be spoofed or manipulated by proxies, resulting in inaccurate IP addresses. To accurately retrieve IP addresses in PHP, the function getIP() can be used to check for multiple server variables that may contain the real IP address of the client. This function tries to get the most accurate IP address by checking various server variables in order of priority. 

function getIP() {
    $ip = $_SERVER['REMOTE_ADDR'];

    if (array_key_exists('HTTP_X_FORWARDED_FOR', $_SERVER)) {
        $forwarded_ips = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
        $ip = trim($forwarded_ips[0]);
    } elseif (array_key_exists('HTTP_CLIENT_IP', $_SERVER)) {
        $ip = $_SERVER['HTTP_CLIENT_IP'];
    } elseif (array_key_exists('HTTP_X_FORWARDED', $_SERVER)) {
        $ip = $_SERVER['HTTP_X_FORWARDED'];
    } elseif (array_key_exists('HTTP_X_CLUSTER_CLIENT_IP', $_SERVER)) {
        $ip = $_SERVER['HTTP_X_CLUSTER_CLIENT_IP'];
    } elseif (array_key_exists('HTTP_FORWARDED_FOR', $_SERVER)) {
        $ip = $_SERVER['HTTP_FORWARDED_FOR'];
    } elseif (array_key_exists('HTTP_FORWARDED', $_SERVER)) {
        $ip = $_SERVER['HTTP_FORWARDED'];
    }

    return $ip;
}

$ip = getIP();
echo "Client IP Address: " . $ip;

Keywords

function getIP() IP addresses PHP $_SERVER

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