gistfile1.php

<?php


function checkEmail($email) {
    // checks proper syntax
    if(preg_match("/^([a-z])([a-z0-9._])+([a-z0-9])\@([a-z0-9])*([a-z])+(-[a-z])*([a-z0-9])*(\.([a-z0-9])*([a-z])+(-[a-z])*([a-z0-9])*)+$/i" , $email)) {
        // gets domain name
        list($username, $domain) = split('@', $email);
        // checks for if MX records in the DNS
        if(checkdnsrr($domain, 'MX')) {
            return true;
        }

    }

    return false;
}

gistfile2.txt

http://gist.github.com/577311 lidt pænere og burde virke.