php tool - Extracting domain names from a zone file?

Question

hi,

i have access to the zone file for a tld. How can I extract just the domain names in the fastest possible way?

Any suggestions on how to store them in a database/file? There are millions of them.

Answer 1

Note, i'm just rattling off code here. This would be the general idea, but the code may need editing. In fact, it almost certainly does.

$fin = fopen('your zone file', 'r');
while (!feof($fin))
{
    $matches = array();
    $line = trim(fgets($fin));
    // only care about lines that are ip addresses or aliases
    if (preg_match('/^(\S+)\s+((?:IN\s+)?)(A|AAAA|CNAME)\s+(\S+)$/i', $line, $matches))
    {
        $subdomain = $matches[1];
        $ip_or_alias = $matches[4];
        do_something($subdomain, $ip_or_alias);
    }
}
fclose($fin);

You'd define a function do_something that would take the info and store it somewhere. Or, put the code right there where the function call is instead.

As for how to store it, that depends a lot on what you're going to do with it.