@PostConstruct
	public void init() {
		String ip = nacosDiscoveryProperties.getIp();
		if (StringUtils.isNotEmpty(ip)) {
			ipv6 = Pattern.matches(IPV4_REGEX, ip) ? nacosDiscoveryProperties.getMetadata().get(IPV6_KEY) : ip;
		}
		else {
			ipv6 = inetIPv6Utils.findIPv6Address();
		}
	}
Storage local valid IPv6 address, it's a flag whether local machine support IPv6 address stack.
spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/loadbalancer/NacosLoadBalancer.java