code: func GuessHostIP() (ip net.IP, err error) {
  	ifaces, err := net.Interfaces()
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	adrs := make([]net.Addr, 0)
  	for _, iface := range ifaces {
  		ifadrs, err := iface.Addrs()
  		if err != nil {
  			log.Warn(err)
  		} else {
  			adrs = append(adrs, ifadrs...)
  		}
  	}
  	return guessHostIP(adrs), nil
  }
docs: // GuessIP tries to guess an IP address this machine is reachable at on the
  // internal network, always picking IPv4 from the internal address space
  //
  // If no internal IPs are found, it returns 127.0.0.1 but it never returns
  // an address from the public IP space