function validateEmailAdvanced($email) // Regular expression validation $pattern = "/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]2,$/"; if (!preg_match($pattern, $email)) return false;
$port = 25; $timeout = 10;
Many servers block this technique, and it can be flagged as abuse.
// Step 3: Check if the domain has MX records if (checkdnsrr($domain, "MX")) return true; else return false;