// skip it to prevent a panic.
			continue
		}
		if addr.Is4() {
			return false
		}
	}
	return true
}

// AllIPv4 checks the addresses slice and returns true if all addresses
// are valid IPv4 address, for all other cases it returns false.
func AllIPv4(ipAddrs []string) bool {
	for i := 0; i < len(ipAddrs); i++ {
		addr, err := netip.ParseAddr(ipAddrs[i])
		if err != nil {

			expected: false,
		},
		{
			name:     "test for invalid ip address",
			addrs:    []string{"invalidip"},
			expected: true,
		},
	}
	for _, tt := range tests {
		result := AllIPv4(tt.addrs)
		if result != tt.expected {
			t.Errorf("Test %s failed, expected: %t got: %t", tt.name, tt.expected, result)
		}
	}
}

func TestGlobalUnicastIP(t *testing.T) {
	tests := []struct {

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 {