title: Regex to validate port number
body: <p>I'm using this regex <code>(6553[0-5]|655[0-2]\d|65[0-4]\d{2}|6[0-4]\d{3}|[1-5]\d{4}|[1-9]\d{0,3}</code> to validate port numbers. Somehow this is not working. What is wrong with this? Can anybody point me out.</p>