servnest-mkosi/srv/servnest/errors/index.php

<?php

http_response_code(404);

if (filter_var(str_replace(array('[', ']'), '', $_SERVER['HTTP_HOST']), FILTER_VALIDATE_IP))
	echo file_get_contents("default-ip.en.html");
else
	echo file_get_contents("default-domain.en.html");