当机器同时存在内网和外网IP时，无法发布内网IP服务

[nevin9939]

Environment

• Dubbo version: 2.7.1
• Operating System version: xxx
• Java version: 1.8.181

Steps to reproduce this issue

1. 服务都是部署在阿里云的ECS上
2. hosts中修改机器名执行本机的内网IP
3. dubbo注册到zookeeper的服务IP是外网IP
4. 原整个环境的dubbo服务均提供内网服务，禁止外网的服务和请求进入，造成服务调不通

查看源代码发现在 request #3520 中调整为优先获取外网IP，造成了当机器同时存在内网IP和外网IP时，期望只提供内网IP服务时就无法做到，个人认为最好有个配置开关，有用户决定是提供内网服务还是外网服务

[ralf0131]

+1 to you proposal, would you like to send a pull request to fix this?

[nevin9939]

I can try it, not a lot of spare time.

[lexburner]

@nevin9939 I send a pull request, could you pls review it and try it to see whether meet your requirement? Thanks.

[nevin9939]

@lexburner
我也写完了 (T_T) ， 看了下我跟你的区别主要在首选网卡的选择，跟操作系统同步，这样可以防止优先获取到虚拟机和蓝牙桥接网卡，你可以加进去。还有，我认为默认值应该是false，因为照原来的逻辑，获取的都是内网IP，这样用户就不会受升级的变化而困扰，去添加额外的配置

    private static InetAddress getLocalAddress0() {
        InetAddress candidateAddress = null;
        int interfacesIndex = 0;
        try {
            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
            if (null != interfaces) {
                while (interfaces.hasMoreElements()) {
                    try {
                        NetworkInterface network = interfaces.nextElement();
                        // Remove loopback interface, subinterface, not running interface
                        if (network.isLoopback() || network.isVirtual() || !network.isUp()) {
                            continue;
                        }
                        Enumeration<InetAddress> addresses = network.getInetAddresses();
                        while (addresses.hasMoreElements()) {
                            try {
                                Optional<InetAddress> addressOp = toValidAddress(addresses.nextElement());
                                if (addressOp.isPresent()) {
                                    InetAddress tempAddress = addressOp.get();
                                    if (candidateAddress == null || interfacesIndex > network.getIndex()) {
                                        // Priority is given to the network card with a small index value,
                                        // which can exclude the IP of the self-built virtual machine.
                                        candidateAddress = tempAddress;
                                        interfacesIndex = network.getIndex();
                                    }
                                }
                            } catch (Throwable e) {
                                logger.warn(e);
                            }
                        }
                    } catch (Throwable e) {
                        logger.warn(e);
                    }
                }
            }
            if(candidateAddress == null){
                InetAddress jdkSuppliedAddress = InetAddress.getLocalHost();
                if (jdkSuppliedAddress == null) {
                    throw new UnknownHostException("The JDK InetAddress.getLocalHost() method unexpectedly returned null.");
                }
                Optional<InetAddress> addressOp = toValidAddress(jdkSuppliedAddress);
                if (addressOp.isPresent()) {
                    candidateAddress = addressOp.get();
                }
            }
        } catch (Throwable e) {
            logger.warn(e);
        }
        return candidateAddress;
    }

[lexburner]

Looks good to me, I will take it as consideration.

[beiwei30]

this sounds like a solid solution to filter out the network interfaces first:

if (network.isLoopback() || network.isVirtual() || !network.isUp()) {
                            continue;
                        }

And, it looks we should either rollback the logic 'isSiteLocalAddress()' or add a flag for it.

[beiwei30]

#3953 enhanced this issue.