/**
* Discover host and port for specified prefix and ports
*
* @param $email
* @param $prefix
* @param $ports
* @return array
* @throws \Exception
*/
private function analyse($email, $prefix, $ports)
{
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
throw new \Exception('Not a valid email');
}
$host = null;
$domain = explode('@', $email);
if ($mxServer = Dns::getTopMx($domain[1])) {
// save MX-server information
$mxServerDomains = explode('.', $mxServer);
$mxServerRoot = implode('.', array_slice($mxServerDomains, -2, 2));
$this->mxServer = $mxServer;
$this->mxServerRoot = $mxServerRoot;
}
if ($port = Socket::pingPort($prefix . $domain[1], $ports)) {
$host = $prefix . $domain[1];
} elseif ($mxServer) {
if ($port = Socket::pingPort($mxServer, $ports)) {
$host = $mxServer;
} else {
$revMxServer = gethostbyaddr(gethostbyname($mxServer));
$revMxServerDomains = explode('.', $revMxServer);
$revMxServerRoot = @implode('.', array_slice($revMxServerDomains, -2, 2));
if ($port = Socket::pingPort($prefix . $revMxServerRoot, $ports)) {
$host = $prefix . $revMxServerRoot;
} else {
if ($port = Socket::pingPort($prefix . $mxServerRoot, $ports)) {
$host = $prefix . $mxServerRoot;
}
}
}
}
return [$host, $port];
}