Simple utility to display external IP for updating dyndns

client_ip.php

<?php

$client_ip = $_SERVER['REMOTE_ADDR'];
$ip_version = (filter_var($client_ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) ?
    '4' :
    '6';

$tz = new DateTimeZone('UTC');
$datetime = new DateTime();
$datetime->setTimezone($tz);

$data = [
    'time' => $datetime->format('c'),
    'ip' => [
        'version' => $ip_version,
        'address' => $client_ip
    ]
];

header('Content-Type: application/json; charset=utf-8');

echo json_encode($data);