    def ip
      addr = Socket.ip_address_list.detect do |i|
        i.ipv4? && !i.ipv4_loopback? && !i.ipv4_multicast? && !i.ipv4_private?
      end
      raise 'Can\'t detect your IP address, you have to specify it in --host' if addr.nil?
      addr.ip_address
    end