What are the potential security risks of using $HTTP_SERVER_VARS["REMOTE_ADDR"] instead of $_SERVER["REMOTE_ADDR"] in PHP scripts?

Using $HTTP_SERVER_VARS["REMOTE_ADDR"] instead of $_SERVER["REMOTE_ADDR"] in PHP scripts can pose a security risk as $HTTP_SERVER_VARS is deprecated and may not always be available, leading to potential vulnerabilities. To mitigate this risk, it is recommended to use $_SERVER["REMOTE_ADDR"] instead for obtaining the client's IP address.

$client_ip = $_SERVER["REMOTE_ADDR"];