Get DNS servers from root servers using dig (hack)

query.php

<?php

function get_ns_from_root($hostname) {
	$regex_hostname = preg_quote($hostname);
	$dig_cmd = "dig +trace {$hostname} | egrep '^{$regex_hostname}\..*IN.*NS' | awk '{ print $5 }'";

	exec($dig_cmd, $nameservers);

	return $nameservers;
}

$hostname = 'buycity.info';
$nameservers = get_ns_from_root($hostname)l

print_r($nameservers);

# Output:
#
# Array
# (
#     [0] => ns4.hosteceran.com.
#     [1] => ns2.hosteceran.com.
#     [3] => ns3.hosteceran.com.
#     [2] => ns1.hosteceran.com.
# )