What are some alternative methods to retrieve the user's IP address in PHP if $HTTP_SERVER_VARS['REMOTE_ADDR'] is not working correctly?

If $HTTP_SERVER_VARS['REMOTE_ADDR'] is not working correctly to retrieve the user's IP address in PHP, you can try using the $_SERVER['REMOTE_ADDR'] variable instead. This variable is a part of the $_SERVER superglobal array which contains information about the server and the request being made. By using $_SERVER['REMOTE_ADDR'], you can ensure that you are getting the correct IP address of the user.

// Alternative method to retrieve user's IP address in PHP
$user_ip = $_SERVER['REMOTE_ADDR'];
echo "User's IP address: " . $user_ip;