[B00MER]

I don't think the default takes Proxies or IP's behind LAN's into consideration. Here's a function that can easily be used in config.php to grab the absolute IP of the user. Thanks to NuLime for the function.

function fetch_remote_address() {
	$_SERVER = $GLOBALS['HTTP_SERVER_VARS'];
	# Record basic remote address.
	 $remote_address = $_SERVER['REMOTE_ADDR'];
	# Take proxies into consideration or IPs behind a LAN.
	if (isset($_SERVER['HTTP_X_FORWARDED_FOR']) && $_SERVER['HTTP_X_FORWARDED_FOR'] != 'unknown' && $_SERVER['HTTP_X_FORWARDED_FOR'] != $_SERVER['REMOTE_ADDR']) {
		$HXFF_temp = preg_replace('/, ?unknown/i','',$_SERVER['HTTP_X_FORWARDED_FOR']); // Remove any trailing 'unknowns'.
		$remote_address .= ','.$HXFF_temp;
	}
	if (isset($_SERVER['HTTP_CLIENT_IP']) && $_SERVER['HTTP_CLIENT_IP'] != 'unknown' && $_SERVER['HTTP_CLIENT_IP'] != $_SERVER['HTTP_X_FORWARDED_FOR'] && $_SERVER['HTTP_CLIENT_IP'] != $_SERVER['REMOTE_ADDR']) {
		$HCI_temp = preg_replace('/, ?unknown/i','',$_SERVER['HTTP_CLIENT_IP']); // Remove any trailing 'unknowns'.
		$remote_address .= ','.$HCI_temp;
	}
	
	return $remote_address;
}