OpenSource email list Cleaning script

I haven't done anything like that in years but the simplest way is just to write a quick php script that runs down the list and checks the mx records to see if it would be deliverable.

Something like this is a step along the way

<?php
function domain_exists($email, $record = 'MX'){
list($user, $domain) = explode('@', $email);
return checkdnsrr($domain, $record);
}
if(domain_exists('sarah@somedomainifound.com')) {
echo('This MX records exists; I will accept this email as valid.');
}
else {
echo('No MX record exists; Invalid email.');
}

Code (markup):