diff --git a/.vscode/launch.json b/.vscode/launch.json
index 9d84663..c34111f 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -6,6 +6,13 @@
     "configurations": [
         {
             "type": "java",
+            "name": "MainMonitor",
+            "request": "launch",
+            "mainClass": "info.istlab.ServerTester.monitor.MainMonitor",
+            "projectName": "KisoServerTester"
+        },
+        {
+            "type": "java",
             "name": "ServerTesterApp",
             "request": "launch",
             "mainClass": "info.istlab.ServerTester.ServerTesterApp",
diff --git a/src/main/java/info/istlab/ServerTester/App.java b/src/main/java/info/istlab/ServerTester/App.java
index 85958d7..cce5be3 100644
--- a/src/main/java/info/istlab/ServerTester/App.java
+++ b/src/main/java/info/istlab/ServerTester/App.java
@@ -20,6 +20,16 @@
         userdir = System.getProperty("user.dir");
     }
 
+    public static void networkSelect(){
+        // ネットワークインタフェースの調査と選択
+        primaryInterface = NetworkInterfaceSelector.getPrimaryInterface();
+        if (primaryInterface == null) {
+            System.out.println("ネットワークインタフェースが見つかりませんでした。");
+            System.exit(1);
+        }
+        primaryInetAddr = NetworkInterfaceSelector.getPrimaryInetAddr(primaryInterface);
+    }
+
     public static void main(String[] args) {
         Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
             @Override
@@ -33,13 +43,8 @@
         String location = clazz.getProtectionDomain().getCodeSource().getLocation().getPath();
         isJAR = location.endsWith(".jar");
 
-        // ネットワークインタフェースの調査と選択
-        primaryInterface = NetworkInterfaceSelector.getPrimaryInterface();
-        if (primaryInterface == null) {
-            System.out.println("ネットワークインタフェースが見つかりませんでした。");
-            System.exit(1);
-        }
-        primaryInetAddr = NetworkInterfaceSelector.getPrimaryInetAddr(primaryInterface);
+        networkSelect();
+
 
         Host myhost = new Host();
 
diff --git a/src/main/java/info/istlab/ServerTester/monitor/MainMonitor.java b/src/main/java/info/istlab/ServerTester/monitor/MainMonitor.java
new file mode 100644
index 0000000..d5cd792
--- /dev/null
+++ b/src/main/java/info/istlab/ServerTester/monitor/MainMonitor.java
@@ -0,0 +1,32 @@
+package info.istlab.ServerTester.monitor;
+
+import java.util.ArrayList;
+
+import info.istlab.ServerTester.App;
+
+public class MainMonitor {
+
+    ArrayList<MulticastMonitor> monitors = new ArrayList<MulticastMonitor>();
+
+    public static void main(String[] args) {
+        App.networkSelect();
+        new MainMonitor();
+    }
+
+    public MainMonitor() {
+        for (int i = 0; i < 10; i++) {
+            monitors.add(new MulticastMonitor(54320 + i, this));
+        }
+    }
+
+    public void processReceivedData(int channel, String addr, String message) {
+        // System.out.println("Received from " + addr + ": " + message);
+        String[] lines = message.split("\n");
+        for (String line : lines) {
+            if (line.indexOf("WebServer") > -1 && line.indexOf("127.0.0.1") == -1
+                    && line.indexOf("Running") > -1) {
+                System.out.println("  " + line + " " + addr + " " + channel);
+            }
+        }
+    }
+}
diff --git a/src/main/java/info/istlab/ServerTester/monitor/MulticastMonitor.java b/src/main/java/info/istlab/ServerTester/monitor/MulticastMonitor.java
new file mode 100644
index 0000000..d42ea2e
--- /dev/null
+++ b/src/main/java/info/istlab/ServerTester/monitor/MulticastMonitor.java
@@ -0,0 +1,91 @@
+package info.istlab.ServerTester.monitor;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.StandardProtocolFamily;
+import java.nio.ByteBuffer;
+import java.nio.channels.AsynchronousCloseException;
+import java.nio.channels.DatagramChannel;
+import java.util.Hashtable;
+
+import info.istlab.ServerTester.App;
+import info.istlab.ServerTester.MulticastSender;
+import info.istlab.ServerTester.RemoteHostsWindow;
+
+public class MulticastMonitor implements Runnable {
+    Thread thread;
+    // MulticastSocket socket;
+    MulticastSender sender;
+    RemoteHostsWindow remoteHostsWindow;
+    DatagramChannel channel;
+
+    // 受信したデータを IP アドレスをキーにして保存
+    Hashtable<String, String> receivedData = new Hashtable<String, String>();
+    MainMonitor mainMonitor;
+    int portNum;
+
+    public MulticastMonitor(int portNum, MainMonitor mainMonitor) {
+        this.mainMonitor = mainMonitor;
+        this.portNum = portNum;
+        try {
+            // socket = new MulticastSocket(portNum);
+            InetAddress group = InetAddress.getByName("224.0.0.1");
+
+            try {
+                channel = DatagramChannel.open(StandardProtocolFamily.INET);
+                channel.bind(new InetSocketAddress(portNum));
+                channel.join(group, App.primaryInterface);
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+            // socket.joinGroup(group);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        thread = new Thread(this);
+        thread.start();
+    }
+
+    public void run() {
+        ByteBuffer buffer = ByteBuffer.allocate(1024);
+        while (thread != null) {
+            buffer.clear();
+            InetSocketAddress senderAddr = null;
+            try {
+                senderAddr = (InetSocketAddress) channel.receive(buffer);
+            } catch(AsynchronousCloseException ace){
+                thread = null;
+                break;
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+            buffer.flip();
+
+            byte[] data = new byte[buffer.remaining()];
+            buffer.get(data);
+            String message = new String(data);
+            if (senderAddr == null) {
+                thread = null;
+                break;
+            }
+            String addr = senderAddr.getAddress().getHostAddress();
+            receivedData.put(addr, message);
+            if (mainMonitor != null) {
+                mainMonitor.processReceivedData(portNum - 54320, addr, message);
+            }
+        }
+    }
+
+    public void stop() {
+        try {
+            channel.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        // socket.close();
+        sender.stop();
+        // thread = null;
+    }
+
+}