PHP: Strict Email VAlidation

email.php

<?php
	/*
		Email Address Validation
		Check the variable $email is a valid email address. 
		
		Usage:
			print validate_email("email@address.com");
		
		Or:
			$email = "email@address.com";
			print validate_email($email);
	*/
		function validate_email($email) {
		  if (!ereg("^[^@]{1,64}@[^@]{1,255}$", $email)) {
		    $return = "$email is not an email address.";
		  }
		  $email_array = explode("@", $email);
		  $local_array = explode(".", $email_array[0]);
		  for ($i = 0; $i < sizeof($local_array); $i++) {
		    if (!ereg("^(([A-Za-z0-9!#$%&'*+/=?^_`{|}~-][A-Za-z0-9!#$%&'*+/=?^_`{|}~\.-]{0,63})|(\"[^(\\|\")]{0,62}\"))$", $local_array[$i])) {
		      $return = "$email is not an email address.";
		    }
		  }
		  if (!ereg("^\[?[0-9\.]+\]?$", $email_array[1])) { // Check if domain is IP. If not, it should be valid domain name
		    $domain_array = explode(".", $email_array[1]);
		      if (sizeof($domain_array) < 2) {
		        $return = "$email is not an email address.";
		      }
		    for ($i = 0; $i < sizeof($domain_array); $i++) {
		      if (!ereg("^(([A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])|([A-Za-z0-9]+))$", $domain_array[$i])) {
		        $return = "$email is not an email address.";
		      }
		    }
		  }
		  $return = "$email is valid email address.";
		return $return;
		}


<?php
$email="test@geemail.com";
if (isValidEmail($email))
{
       echo "Hooray! Adress is correct.";
}
else
{
       echo "Sorry! No way.";
}

//Check-Function
function isValidEmail($email)
{
       //Perform a basic syntax-Check
       //If this check fails, there's no need to continue
       if(!filter_var($email, FILTER_VALIDATE_EMAIL))
       {
               return false;
       }

       //extract host
       list($user, $host) = explode("@", $email);
       //check, if host is accessible
       if (!checkdnsrr($host, "MX") && !checkdnsrr($host, "A"))
       {
               return false;
       }

       return true;
}
?>