- var_dump: documentation ( source)
- filter_var: documentation ( source)
<?php
var_dump(filter_var('127.0.0.1', FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_IPV6));
var_dump(filter_var('::1', FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_IPV6));