}
	ip, ok := hasRoutableIP(network, ifi)
	if !ok {
		return nil, errNoAvailableAddress
	}
	return ip, nil
}

// LoopbackInterface returns an available logical network interface
// for loopback test.
func LoopbackInterface() (*net.Interface, error) {
	ift, err := net.Interfaces()
	if err != nil {
		return nil, errNoAvailableInterface
	}
	for _, ifi := range ift {

		resolveIPAddrTests = append(resolveIPAddrTests, resolveIPAddrTest{"ip", "::", &IPAddr{IP: IPv6unspecified}, nil})
	}

	ifi := loopbackInterface()
	if ifi != nil {
		index := fmt.Sprintf("%v", ifi.Index)
		resolveTCPAddrTests = append(resolveTCPAddrTests, []resolveTCPAddrTest{