Check to see if ip address comes from a Tor proxy

TorProxy.php

<?php
class TorProxy
{
    /**
     * Is IP address a Tor proxy ip address.
     * See https://lists.torproject.org/pipermail/tor-project/2020-March/002759.html
     *
     * @param $ip
     * @return bool
     */
    public static function isTorIpAddress(string $ip): bool
    {
        $host = implode('.', array_reverse(explode('.', $ip))) . '.dnsel.torproject.org';
        return !empty(dns_get_record($host));
    }
}