An IP address. (0|(1[0-9]{0,2})|(2(([0-4][0-9]?)|(5[0-5]?)|[6-9])?)|([3-9][0-9]?))(\.(0|(1[0-9]{0,2})|(2(([0-4][0-9]?)|(5[0-5]?)|[6-9])?)|([3-9][0-9]?))){3}