title: How to check domain nameservers in PHP?
body: <p>I need check what nameservers domain is using, but can't find correct solution in PHP.</p>
  
  <p>I have tried <code>checkdnsrr();</code> and <code>dns_get_record();</code>, both of them do not show NS for some of domains that are working. <code>Whois</code> is also not a solution.</p>
  
  <p>My purpose is to filter domains which have nameserver set and which haven't. Is there any solution for this?</p>