Amazing how so many people have such long and complex answers to a simple question.
Question: How do you validate a email address in PHP5?
Answer: 	function validemail($var) {
		if (filter_var(filter_var($var, FILTER_SANITIZE_EMAIL), FILTER_VALIDATE_EMAIL)) {
			list($username,$domain)=split('@',$var);
				if(!checkdnsrr($domain,'MX')) {
				return false;
				}
				return true;
			}
		return false;
	}
Damn people…. it wasn’t that hard!!! Once I gave up on other peoples answers, I decided to get my head on straight and did that.
Next, will be a easy was to handle a sub domain MX record…