<?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.<br>");
			}else{
			print("$email is ok. But domain is not.<br>");
			}
				}else{
				print("$email is not ok.<br>");
				}   
}

validate_email("shantanu.ok");
validate_email("shantanu.ok@gmail.com");
validate_email("shantanu.ok@fsjaldkfjlsfjsljflsfjsldk.com");

?>