How to catch dyndns via php

Question

I’d like to take the ip who is in the dyndns via PHP.

1. It is possible to do this??
2. If so, where do I start researching?

Answer 1

Use the gethostbyname, it will return the IP (Ipv4) corresponding to the address, example:

<?php
$ip = gethostbyname('meu_host_foo_bar.dyndns.org');

echo $ip;

An important detail is that if the gethostbyname fail to get the ip address it will return the host itself which might confuse, so you can check like this:

<?php
$hostname = 'meu_host_foo_bar.dyndns.org';
$ip = gethostbyname($hostname);

if ($ip === $hostname) {
    echo 'Falha ao obter o IP de: ', $hostname;
} else {
    echo 'IP:', $ip;
}

Note that you can try using gethostbynamel which will return a list in an array corresponding to the hostname passed:

<?php
$hostname = 'meu_host_foo_bar.dyndns.org';
$ips = gethostbynamel($hostname);

if (!$hosts) {
    echo 'Falha ao obter o IP de: ', $hostname;
} else {
    print_r($hosts);
}

Will return something like:

Array
(
    [0] => 192.0.34.166
)

That is, depending on the service you can return more than one, so you can check which is what you need. Failure will return false.