BitchAssCode

This is a super short post but i just wanted to share it because i’m currently doing a DNS migration and finding that validating all CNAME and A records for our domain isnt super easy. Here is how i ended up doing it (You should re-use this PHP!):

//name servers to compare against
$nameservers = array();
array_push($nameservers,"ns1.origionalnameserver.com");
array_push($nameservers,"ns2.origionalnameserver.com");
array_push($nameservers,"ns1.destinationnameserver.com");
array_push($nameservers,"ns2.destinationnameserver.com");

//hosts to compare
$hosts = array(
"hostname1.com",
"hostname2.com",
"hostname3.com",
"hostname4.com"
);

//do the compare and echo out the results
foreach($hosts as $host)
{
//get the results for each name server given the current host
$results = array();
foreach($nameservers as $ns)
{
$result = getDNS($host,$ns);
array_push($results,strtolower($result));
//echo "LOG: $host $ns - $result\n";
}

//see if all the results match
$allmatch = true;
$compare_result = $results[0];
foreach($results as $result)
{
if($result != $compare_result)
$allmatch = false;
}

//check to see if everything matched or not
if(!$allmatch)
{
echo "WARN: $host does not match on all nameservers\n";
$count = 0;
foreach($results as $result)
{
echo "[".$nameservers[$count]."] $result\n";
++$count;
}
}
else
{
echo "INFO: $host OK\n";
}
}

//getdns function to get host name given a name server
function getDNS($host,$ns)
{
$string = '';
exec("dig @$ns +short $host 2>&1", $output, $retval);
if ($retval != 0)
{
return "ERROR_NO_RESULT";
}
else
{
$x=0;
while ($x < (sizeof($output)))
{
$string.= $output[$x];
$x++;
}
}

if (empty($string))
{
return "ERROR_NO_RESULT";
}
else if($string[strlen($string)-1] == '.')
{
$string = substr($string, 0, -1);
}

return $string;
}