diff --git a/src/main/java/info/istlab/ServerTester/App.java b/src/main/java/info/istlab/ServerTester/App.java
index 2eda36a..c56ff05 100644
--- a/src/main/java/info/istlab/ServerTester/App.java
+++ b/src/main/java/info/istlab/ServerTester/App.java
@@ -69,7 +69,6 @@
 
         // 近隣のホスト情報を集めるUDPサーバ
         // myhost.setUdpServer(new UDPServer(54320));
-        new MulticastSender();
-        new MulticastReceiver();
+        myhost.setMulticastReceiver(new MulticastReceiver(54320));
     }
 }
diff --git a/src/main/java/info/istlab/ServerTester/Host.java b/src/main/java/info/istlab/ServerTester/Host.java
index e4442bd..367f4da 100644
--- a/src/main/java/info/istlab/ServerTester/Host.java
+++ b/src/main/java/info/istlab/ServerTester/Host.java
@@ -14,7 +14,7 @@
     public static Host mainhost;
     public JPanel mainPanel;
 
-    public UDPServer udpServer;
+    public MulticastReceiver multicastReceiver;
 
     public Host() {
         setTitle("サーバ管理ウィンドウ");
@@ -34,8 +34,8 @@
         // udpServer = new UDPServer();
     }
 
-    public void setUdpServer(UDPServer udpServer) {
-        this.udpServer = udpServer;
+    public void setMulticastReceiver(MulticastReceiver mr) {
+        multicastReceiver = mr;
     }
 
     private void setupMenu() {
@@ -44,35 +44,35 @@
         JMenu menu = new JMenu("Menu");
         menuBar.add(menu);
 
-        JMenu channel = new JMenu("班の番号を選択（UDPサーバの再起動）");
+        JMenu channel = new JMenu("班の番号を選択（マルチキャストアドレスの変更）");
         menu.add(channel);
         for (int i = 0; i <= 9; i++) {
             JMenuItem item = new JMenuItem(String.valueOf(i));
             channel.add(item);
             item.addActionListener(e -> {
                 System.out.println("班の番号: " + item.getText());
-                if (udpServer != null) {
-                    udpServer.stop();
+                if (multicastReceiver != null) {
+                    multicastReceiver.stop();
                     try {
                         Thread.sleep(1000);
                     } catch (InterruptedException e1) {
                         e1.printStackTrace();
                     }
                 }
-                udpServer = new UDPServer(54320 + Integer.parseInt(item.getText())); // 54320 + 班の番号 のポート番号で待つ
+                multicastReceiver = new MulticastReceiver(54320 + Integer.parseInt(item.getText())); // 54320 + 班の番号 のポート番号で待つ
             });
         }
 
-        JMenuItem sendItem = new JMenuItem("このホストのサーバ情報をブロードキャストで送信");
-        menu.add(sendItem);
-        sendItem.addActionListener(e -> {
-            new UDPClient(mainPanel, udpServer.port);
-        });
+        // JMenuItem sendItem = new JMenuItem("このホストのサーバ情報をブロードキャストで送信");
+        // menu.add(sendItem);
+        // sendItem.addActionListener(e -> {
+        //     new UDPClient(mainPanel, udpServer.port);
+        // });
 
         JMenuItem showItem = new JMenuItem("近隣ホストのサーバ情報を表示");
         menu.add(showItem);
         showItem.addActionListener(e -> {
-            udpServer.openWindow();
+            multicastReceiver.openWindow();
         });
 
         menu.addSeparator();
diff --git a/src/main/java/info/istlab/ServerTester/MulticastReceiver.java b/src/main/java/info/istlab/ServerTester/MulticastReceiver.java
index 7d647a9..534d812 100644
--- a/src/main/java/info/istlab/ServerTester/MulticastReceiver.java
+++ b/src/main/java/info/istlab/ServerTester/MulticastReceiver.java
@@ -4,18 +4,22 @@
 import java.net.DatagramPacket;
 import java.net.InetAddress;
 import java.net.MulticastSocket;
+import java.net.SocketException;
 import java.util.Hashtable;
 
+import javax.swing.JOptionPane;
+
 public class MulticastReceiver implements Runnable{
     Thread thread;
     MulticastSocket socket;
+    MulticastSender sender;
 
     // 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>();
 
-    public MulticastReceiver() {
+    public MulticastReceiver(int portNum) {
         try {
-            socket = new MulticastSocket(54320);
+            socket = new MulticastSocket(portNum);
             InetAddress group = InetAddress.getByName("224.0.0.1");
             socket.joinGroup(group);
         } catch (IOException e) {
@@ -23,6 +27,7 @@
         }
         thread = new Thread(this);
         thread.start();
+        sender = new MulticastSender(portNum);
     }
 
     public void run(){
@@ -31,6 +36,8 @@
             DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
             try {
                 socket.receive(packet);
+            } catch(SocketException sx) {
+                thread = null;
             } catch (IOException e) {
                 e.printStackTrace();
             }
@@ -39,7 +46,19 @@
             receivedData.put(addr, message);
 
             System.out.println(addr+"からの受信: " + message);
-
         }
     }
+    public void stop(){
+        socket.close();
+        sender.stop();
+        // thread = null;
+    }
+
+    public void openWindow() {
+        if (receivedData.size() == 0) {
+            JOptionPane.showMessageDialog(Host.mainhost, "受信したデータがありません。", "受信データなし", JOptionPane.WARNING_MESSAGE);
+            return;
+        }
+        new RemoteHostsWindow(receivedData);
+    }
 }
diff --git a/src/main/java/info/istlab/ServerTester/MulticastSender.java b/src/main/java/info/istlab/ServerTester/MulticastSender.java
index 606550b..713bfdc 100644
--- a/src/main/java/info/istlab/ServerTester/MulticastSender.java
+++ b/src/main/java/info/istlab/ServerTester/MulticastSender.java
@@ -12,15 +12,14 @@
 
     Thread thread;
     MulticastSocket socket = null;
-    public String message;
-    String multicastAddress = "224.0.0.1"; // マルチキャストアドレス
     public int port = 54320;
     InetAddress group;
     
-    public MulticastSender() {
+    public MulticastSender(int portNum) {
+        port = portNum;
         try {
             socket = new MulticastSocket();
-            group = InetAddress.getByName(multicastAddress);
+            group = InetAddress.getByName("224.0.0.1");
         } catch (IOException e) {
             e.printStackTrace();
         }
@@ -41,14 +40,15 @@
             } catch (IOException e) {
                 e.printStackTrace();
             }
-
             try {
                 Thread.sleep(5000);
             } catch (InterruptedException e) {
                 e.printStackTrace();
             }
         }
-
+    }
+    public void stop(){
+        thread = null;
     }
 
     private String getServerInfo() {
diff --git a/src/main/java/info/istlab/ServerTester/UDPServer.java b/src/main/java/info/istlab/ServerTester/UDPServer.java
index ddb64e5..6368c45 100644
--- a/src/main/java/info/istlab/ServerTester/UDPServer.java
+++ b/src/main/java/info/istlab/ServerTester/UDPServer.java
@@ -94,11 +94,5 @@
         }
     }
 
-    public void openWindow() {
-        if (receivedData.size() == 0) {
-            JOptionPane.showMessageDialog(Host.mainhost, "受信したデータがありません。", "受信データなし", JOptionPane.WARNING_MESSAGE);
-            return;
-        }
-        new RemoteHostsWindow(receivedData);
-    }
+    
 }