def add_address(ipaddress, rule)
      return false unless rule.is_a?(Rule)
      @addresses ||= {}
      (@addresses[ipaddress] ||= []) << rule
      rule
    end
def add_address(ipaddress, rule)
      return false unless rule.is_a?(Rule)
      @addresses ||= {}
      (@addresses[ipaddress] ||= []) << rule
      rule
    end
* +ipaddress+ is a String, ipaddress/mask/protocol
 * +rule+ is a Rule object