Vérifier une adresse mail

test_mail.php

<?php
    function is_valid_email($email, $test_mx = false) {  
        if(eregi("^([_a-z0-9-]+)(\.[_a-z0-9-]+)*@([a-z0-9-]+)(\.[a-z0-9-]+)*(\.[a-z]{2,4})$", $email))  
            if($test_mx)  
            {  
                list($username, $domain) = split("@", $email);  
                return getmxrr($domain, $mxrecords);  
            }  
            else  
                return true;  
        else  
            return false;  
    }