type IPMode int

// IPMode constants starting with index 1.
const (
	IPv4 IPMode = iota + 1
	IPv6
	Dual
)

func DiscoverIPMode(addrs []string) IPMode {
	if networkutil.AllIPv4(addrs) {
		return IPv4
	} else if networkutil.AllIPv6(addrs) {
		return IPv6
	}
	return Dual

	opts = append(opts, getNodeMetadataOptions(cfg.Node, cfg.CompliancePolicy)...)

	// Check if nodeIP carries IPv4 or IPv6 and set up proxy accordingly
	if network.AllIPv4(cfg.Metadata.InstanceIPs) {
		// IPv4 only
		opts = append(opts,
			option.Localhost(option.LocalhostIPv4),
			option.Wildcard(option.WildcardIPv4),
			option.DNSLookupFamily(option.DNSLookupFamilyIPv4))

		CommonLbConfig:       &cluster.Cluster_CommonLbConfig{},
	}
	switch discoveryType {
	case cluster.Cluster_STRICT_DNS, cluster.Cluster_LOGICAL_DNS:
		if networkutil.AllIPv4(cb.proxyIPAddresses) {
			// IPv4 only
			c.DnsLookupFamily = cluster.Cluster_V4_ONLY
		} else if networkutil.AllIPv6(cb.proxyIPAddresses) {
			// IPv6 only
			c.DnsLookupFamily = cluster.Cluster_V6_ONLY
		} else {