[PHP] E-Mail Verifier

[Gonzalez]

if (!function_exists("checkdnsrr"))
{
    function checkdnsrr($host, $type="")
    {
        if (!empty($host))
        {
            if ($type == "")
                $type = "MX";
            @exec("nslookup -type=" . $type . " " . $host, $output);
            while (list($k, $line) = each($output))
            {
                if (eregi("^" . $host, $line))
                    return true;
            }
            return false;
        }
    }
}

function check_email($e)
{ 
    if ((preg_match("/(@.*@)|(\.\.)|(@\.)|(\.@)|(^\.)/", $e)) || (preg_match("/^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?)$/", $e)))
    { 
        $h = explode('@', $e);
        if (checkdnsrr($h[1] . '.', "MX"))
            return true;
        if (checkdnsrr($h[1] . '.', 'A'))
            return true;
        if (checkdnsrr($h[1] . '.', "CNAME"))
            return true;
    }
    return false;
}

if (check_email("webmsater@nasa.gov"))
    spam("webmaster@nasa.gov"); // spam() not included in this snippet.