querying for SOA but got CNAME instead of empty answer or error

[deepika-maj]

here is the code:

$loop = LoopFactory::create();
$executor = new TcpTransportExecutor('8.8.8.8:53', $loop);

$query = new Query('chrome.blogspot.com', Message::TYPE_SOA, Message::CLASS_IN);

$executor->query($query)->then(function (Message $message) {
    var_export((array)$message);
});

$loop->run();

and response:

array (
  'id' => 35669,
  'qr' => true,
  'opcode' => 0,
  'aa' => false,
  'tc' => false,
  'rd' => true,
  'ra' => true,
  'rcode' => 0,
  'questions' => 
  array (
    0 => 
    React\Dns\Query\Query::__set_state(array(
       'name' => 'chrome.blogspot.com',
       'type' => 6,
       'class' => 1,
    )),
  ),
  'answers' => 
  array (
    0 => 
    React\Dns\Model\Record::__set_state(array(
       'name' => 'chrome.blogspot.com',
       'type' => 5,
       'class' => 1,
       'ttl' => 2864,
       'data' => 'blogspot.l.googleusercontent.com',
    )),
  ),
  'authority' => 
  array (
    0 => 
    React\Dns\Model\Record::__set_state(array(
       'name' => 'l.googleusercontent.com',
       'type' => 6,
       'class' => 1,
       'ttl' => 59,
       'data' => 
      array (
        'mname' => 'ns1.google.com',
        'rname' => 'dns-admin.google.com',
        'serial' => 271311469,
        'refresh' => 900,
        'retry' => 900,
        'expire' => 1800,
        'minimum' => 60,
      ),
    )),
  ),
  'additional' => 
  array (
  ),
)

[Christian Lück]

@deepika-maj Thanks for this excellent question!

What you're seeing may be confusing, but is actually by design. The lower-level executor classes will simply expose the DNS data as-is. If the DNS server responds with a CNAME record instead of your type, it will be returned as-is. This means that you will need to follow the CNAME and do another lookup depending on your use case.

For most higher-level queries, you would normally use the resolve()/resolveAll() methods directory. These methods will take care of resolving any alias names automatically.

I hope this helps 👍

[deepika-maj]

@clue thanks for the clarification