Validare esistenza indirizzo email con php

On 08.16.08, In php, tutorials, by

< ?php
function validate_email($email){
$exp = "^[a-z\'0-9]+([._-][a-z\'0-9]+)*@([a-z0-9]+([._-][a-z0-9]+))+$";
if(eregi($exp,$email)){
if(checkdnsrr(array_pop(explode("@",$email)),"MX")){
print("$email is ok.
");
}else{
print("$email is ok. But domain is not.
");
}
}else{
print("$email is not ok.
");
}
}
validate_email("blablallalb.ddddd");
validate_email("sandrostracuzzi@gmail.com");
validate_email("blablallalb@fbllbalblalblablblbla.com");
?>