checkdnsrr always returns false on windows

Question

I am using checkdnsrr on Windows with PHP 5.3 and it always returns false.

dns_get_record, however, works.

echo ("test.com dns check: ". checkdnsrr("test.com","NS")); //false!!
print_r(dns_get_record("test.com",DNS_NS)); //returns the right data

Answer 1

I guess I found something (tried on windows, PHP 5.3.0, from CLI) :

When I do this :

$tests = array('A', 'MX', 'NS', 'SOA', 'PTR', 'CNAME', 'AAAA', 'A6', 'SRV', 'NAPTR', 'TXT', 'ANY');
foreach ($tests as $type) {
  echo "  Type = $type : ";
  var_dump(checkdnsrr("test.com", $type));
}

I get this :

C:\bin\php-5.3\tests>c:\bin\php-5.3\php.exe test-dns.php
bool(true)
test.com dns check:
  Type = A : bool(false)
  Type = MX : bool(false)
  Type = NS : bool(false)
  Type = SOA : bool(false)
  Type = PTR : bool(false)
  Type = CNAME : bool(false)
  Type = AAAA : bool(false)
  Type = A6 : bool(false)
  Type = SRV : bool(false)
  Type = NAPTR : bool(false)
  Type = TXT : bool(false)
  Type = ANY : bool(false)

So, none of the tests gives "true" :-(

But when I try with another domain :

$tests = array('A', 'MX', 'NS', 'SOA', 'PTR', 'CNAME', 'AAAA', 'A6', 'SRV', 'NAPTR', 'TXT', 'ANY');
foreach ($tests as $type) {
  echo "  Type = $type : ";
  var_dump(checkdnsrr("pascal-martin.fr", $type));
}

(tested on this one because I know what's on it, and wanted to test for a specific idea ^^ )

I get :

C:\bin\php-5.3\tests>c:\bin\php-5.3\php.exe test-dns.php
bool(true)
test.com dns check:
  Type = A : bool(true)
  Type = MX : bool(true)
  Type = NS : bool(true)
  Type = SOA : bool(true)
  Type = PTR : bool(true)
  Type = CNAME : bool(true)
  Type = AAAA : bool(true)
  Type = A6 : bool(true)
  Type = SRV : bool(true)
  Type = NAPTR : bool(true)
  Type = TXT : bool(true)
  Type = ANY : bool(true)

So, the function seems to be working... For at least some domains !

Why could that be ?

Maybe there's something not configured on the DNS server of test.com ? And that something is configured on pascal-martin.fr ?

I don't know DNS systems well enough to tell :-(

Here a couple of outputs from some commands (from Linux) :

$ dig pascal-martin.fr

; <<>> DiG 9.5.1-P2 <<>> pascal-martin.fr
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22164
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;pascal-martin.fr.              IN      A

;; ANSWER SECTION:
pascal-martin.fr.       86400   IN      A       213.186.33.2

;; Query time: 29 msec
;; SERVER: 212.27.40.241#53(212.27.40.241)
;; WHEN: Fri Aug  7 00:00:47 2009
;; MSG SIZE  rcvd: 50

and :

$ dig test.com

; <<>> DiG 9.5.1-P2 <<>> test.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62572
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;test.com.                      IN      A

;; ANSWER SECTION:
test.com.               7200    IN      A       204.12.0.50

;; Query time: 136 msec
;; SERVER: 212.27.40.241#53(212.27.40.241)
;; WHEN: Fri Aug  7 00:00:51 2009
;; MSG SIZE  rcvd: 42

Seems to be almost the same... so not a problem here ?

Let's try another one :

$ host pascal-martin.fr
pascal-martin.fr has address 213.186.33.2
pascal-martin.fr mail is handled by 100 mxb.ovh.net.
pascal-martin.fr mail is handled by 1 mx0.ovh.net.

And :

$ host test.com
test.com has address 204.12.0.50

Well, here, there is a difference ! Might the problem be caused by the fact that test.com resolves to an IP, but has no MX entry ? Or something like this ?

Maybe it is : when I use dns_get_record to test for MX DNS entries, I have no result for test.com :

array(0) {
}

But I have two for pascal-martin.fr :

array(2) {
  [0]=>
  array(6) {
    ["host"]=>
    string(16) "pascal-martin.fr"
    ["type"]=>
    string(2) "MX"
    ["pri"]=>
    int(100)
    ["target"]=>
    string(11) "mxb.ovh.net"
    ["class"]=>
    string(2) "IN"
    ["ttl"]=>
    int(14481)
  }
  [1]=>
  array(6) {
    ["host"]=>
    string(16) "pascal-martin.fr"
    ["type"]=>
    string(2) "MX"
    ["pri"]=>
    int(1)
    ["target"]=>
    string(11) "mx0.ovh.net"
    ["class"]=>
    string(2) "IN"
    ["ttl"]=>
    int(14481)
  }
}

Well, I don't really know "why"... But at least here are a few pointers...

I can't find anything else in the php documentation ; so, I don't know if it's intended behaviour or not :-(

Anyway : good luck !

---

EDIT : well, there might really be some kind of problem under windows, because when I try with Linux, I get :

For test.com :

$ php temp.php
  Type = A : bool(true)
  Type = MX : bool(false)
  Type = NS : bool(true)
  Type = SOA : bool(true)
  Type = PTR : bool(false)
  Type = CNAME : bool(false)
  Type = AAAA : bool(false)
  Type = A6 : bool(false)
  Type = SRV : bool(false)
  Type = NAPTR : bool(false)
  Type = TXT : bool(false)
  Type = ANY : bool(true)

And, for pascal-martin.fr :

$ php temp.php
  Type = A : bool(true)
  Type = MX : bool(true)
  Type = NS : bool(true)
  Type = SOA : bool(true)
  Type = PTR : bool(false)
  Type = CNAME : bool(false)
  Type = AAAA : bool(false)
  Type = A6 : bool(false)
  Type = SRV : bool(false)
  Type = NAPTR : bool(false)
  Type = TXT : bool(false)
  Type = ANY : bool(true)

So, not the same thing (always true or always false) I got on windows...

Maybe there something like, on windows, the function is always looking for MX entry, not taking into account the second parameter ?
(Just a really wild guess ^^)

Answer 2

This functionality is not available on versions of PHP on windows before 5.3.0

See the changelog at php.net's manual page for checkdnsrr for information. Also check the comments for replacements.