<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have searched the <a href="https://github.com/apache/dubbo/issues">issues</a> of this repository and believe that this is not a duplicate.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have checked the <a href="https://github.com/apache/dubbo/blob/master/FAQ.md">FAQ</a> of this repository and believe that this is not a duplicate.</li>
</ul>
<h3 dir="auto">Environment</h3>
<ul dir="auto">
<li>Dubbo version: 2.7.4.1</li>
<li>Operating System version: win7</li>
<li>Java version: 1.8</li>
</ul>
<p dir="auto">Java Code：<br>
package com.ghy.www;</p>
<p dir="auto">import com.ghy.www.dubbo.provider.service.ISayHello;<br>
import com.ghy.www.dubbo.provider.service.SayHello;<br>
import org.apache.dubbo.config.ApplicationConfig;<br>
import org.apache.dubbo.config.RegistryConfig;<br>
import org.apache.dubbo.config.ServiceConfig;</p>
<p dir="auto">import java.io.IOException;</p>
<p dir="auto">public class Application1 {<br>
public static void main(String[] args) throws IOException {<br>
SayHello helloService = new SayHello();<br>
// 服务配置<br>
ServiceConfig serviceConfig = new ServiceConfig();<br>
// 设置应用名称<br>
serviceConfig.setApplication(new ApplicationConfig("dubbo2-server"));<br>
// 设置注册中心<br>
serviceConfig.setRegistry(new RegistryConfig("multicast://224.5.6.7:1234?unicast=false"));<br>
// 设置业务接口<br>
serviceConfig.setInterface(ISayHello.class);<br>
// 设置业务实现类<br>
serviceConfig.setRef(helloService);<br>
// 发布服务<br>
serviceConfig.export();<br>
// 进程不销毁<br>
System.in.read();</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="}"><pre class="notranslate"><code class="notranslate">}
</code></pre></div>
<p dir="auto">}</p>
<p dir="auto">run after show WARN：<br>
main  WARN multicast.MulticastRegistry:  [DUBBO] Ignore empty notify urls for subscribe url provider://192.168.61.250:20880/com.ghy.www.dubbo.provider.service.ISayHello?anyhost=true&amp;application=dubbo2-server&amp;bind.ip=192.168.61.250&amp;bind.port=20880&amp;category=configurators&amp;check=false&amp;deprecated=false&amp;dubbo=2.0.2&amp;dynamic=true&amp;generic=false&amp;interface=com.ghy.www.dubbo.provider.service.ISayHello&amp;methods=sayHello&amp;pid=9900&amp;release=2.7.4.1&amp;side=provider&amp;timestamp=1572321725880, dubbo version: 2.7.4.1, current host: 192.168.61.250</p>
<p dir="auto">why ?<br>
thank very much!</p>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have searched the <a href="https://github.com/apache/incubator-dubbo/issues">issues</a> of this repository and believe that this is not a duplicate.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the <a href="https://github.com/apache/incubator-dubbo/blob/master/FAQ.md">FAQ</a> of this repository and believe that this is not a duplicate.</li>
</ul>
<h3 dir="auto">Environment</h3>
<ul dir="auto">
<li>Dubbo version: 2.7.0</li>
<li>Operating System version: mac</li>
<li>Java version: 1.8</li>
</ul>
<h3 dir="auto">Steps to reproduce this issue</h3>
<ol dir="auto">
<li><code class="notranslate">AbstractClient#initConnectStatusCheckCommand</code> set break point at <code class="notranslate">  !isConnected()</code>.</li>
<li><code class="notranslate">AbstractClient#close()</code> set break point here.</li>
<li>start client first, start provider and then shutdown provider gracefully , let method <code class="notranslate">AbstractClient.close()</code> be executed. Then select step <code class="notranslate">1</code> and trigger the thread to execute <code class="notranslate">!isConnected</code>, here will always try to connect the offline machine.</li>
</ol>
<p dir="auto">Pls. provide [GitHub address] to reproduce this issue.</p>
<h3 dir="auto">Expected Result</h3>
<p dir="auto">What do you expected from the above steps？</p>
<p dir="auto">When the server goes offline, the client will not reconnect the offline machine.</p>
<h3 dir="auto">Actual Result</h3>
<p dir="auto">What actually happens?</p>
<p dir="auto">The client reconnects the offline machine every 2 seconds and causes a large number of arp packets(because ip is recycled and not available now).</p>