diff --git a/ws2012/P2P/uebungen/2/p2p_ex2/src/client/BufferedNetworkStackClient.java b/ws2012/P2P/uebungen/2/p2p_ex2/src/client/BufferedNetworkStackClient.java
index be8eee9e..aa042a0d 100644
--- a/ws2012/P2P/uebungen/2/p2p_ex2/src/client/BufferedNetworkStackClient.java
+++ b/ws2012/P2P/uebungen/2/p2p_ex2/src/client/BufferedNetworkStackClient.java
@@ -9,7 +9,7 @@ import common.MessageType;
 import common.Util;
 
 public class BufferedNetworkStackClient {
-	protected static final long TIMEOUT = 5000;
+	protected static final long TIMEOUT = 3000;
 
 	protected static final int BUF_SIZE = 2048;
 
@@ -28,7 +28,7 @@ public class BufferedNetworkStackClient {
 
 		InetSocketAddress dest = new InetSocketAddress(host, port);
 
-		buf.clear();
+		buf = ByteBuffer.allocate(BUF_SIZE);
 		buf.put(MessageType.CMD_PUSH);
 
 		buf.putInt(s.length());
@@ -66,7 +66,7 @@ public class BufferedNetworkStackClient {
 
 		for (int chunkId = 0; chunkId < numChunks; chunkId++) {
 			buf.flip();
-			buf.clear();
+			buf = ByteBuffer.allocate(BUF_SIZE);
 
 			buf.put(MessageType.CMD_DATA);
 			buf.putInt(sessionId);
@@ -85,7 +85,7 @@ public class BufferedNetworkStackClient {
 
 			try {
 				channel.send(buf, dest);
-				buf.clear();
+				buf = ByteBuffer.allocate(BUF_SIZE);
 			} catch (IOException e) {
 				e.printStackTrace();
 			}
@@ -97,6 +97,7 @@ public class BufferedNetworkStackClient {
 		if (channel == null) {
 			channel = DatagramChannel.open();
 		}
+		buf = ByteBuffer.allocate(BUF_SIZE);
 
 		InetSocketAddress dest = new InetSocketAddress(host, port);
 		channel.send(ByteBuffer.wrap(new byte[] { MessageType.CMD_POP }), dest);
diff --git a/ws2012/P2P/uebungen/2/p2p_ex2/src/client/ClientGUI.java b/ws2012/P2P/uebungen/2/p2p_ex2/src/client/ClientGUI.java
index 70f4f243..84960a87 100644
--- a/ws2012/P2P/uebungen/2/p2p_ex2/src/client/ClientGUI.java
+++ b/ws2012/P2P/uebungen/2/p2p_ex2/src/client/ClientGUI.java
@@ -19,7 +19,7 @@ import javax.swing.border.EmptyBorder;
 public class ClientGUI extends JFrame {
 
 	private JPanel contentPane;
-	private JTextField userinput;
+	private JTextField txtMsg;
 	private JTextField txtPort;
 	private JScrollPane scrollPane;
 	private JTextPane textPane;
@@ -46,6 +46,7 @@ public class ClientGUI extends JFrame {
 	 * Create the frame.
 	 */
 	public ClientGUI() {
+		setTitle("BufferedNetworkStack Client");
 		setResizable(false);
 		client = new BufferedNetworkStackClient();
 
@@ -79,10 +80,10 @@ public class ClientGUI extends JFrame {
 		JLabel lblMessage = new JLabel("Message:");
 		panelPref.add(lblMessage);
 
-		userinput = new JTextField();
-		userinput.setText("asd");
-		panelPref.add(userinput);
-		userinput.setColumns(10);
+		txtMsg = new JTextField();
+		txtMsg.setText("Enter a message");
+		panelPref.add(txtMsg);
+		txtMsg.setColumns(10);
 
 		JButton btnPush = new JButton("Push");
 		panelPref.add(btnPush);
@@ -98,10 +99,12 @@ public class ClientGUI extends JFrame {
 							Integer.valueOf(txtPort.getText()));
 				} catch (NumberFormatException e1) {
 					textPane.setText(textPane.getText()
-							+ "\nErroneous port number. " + e1.getMessage());
+							+ "Erroneous port number. " + e1.getMessage()
+							+ "\n");
 				} catch (IOException e1) {
 					textPane.setText(textPane.getText()
-							+ "\nCould not send to server. " + e1.getMessage());
+							+ "Could not send to server. " + e1.getMessage()
+							+ "\n");
 				}
 			}
 		});
@@ -112,35 +115,51 @@ public class ClientGUI extends JFrame {
 				try {
 					received = client.pop(txtHost.getText(),
 							Integer.valueOf(txtPort.getText()));
-					textPane.setText(textPane.getText() + "\nPopped: "
-							+ received);
+					textPane.setText(textPane.getText() + "Popped: " + received
+							+ "\n");
 				} catch (NumberFormatException e1) {
 					textPane.setText(textPane.getText()
-							+ "\nErroneous port number. " + e1.getMessage());
+							+ "Erroneous port number. " + e1.getMessage()
+							+ "\n");
 				} catch (TimeoutException e2) {
-					textPane.setText(textPane.getText() + "\nServer timed out."
-							+ e2.getMessage());
+					textPane.setText(textPane.getText() + "Server timed out."
+							+ e2.getMessage() + "\n");
 				} catch (IOException e1) {
 					textPane.setText(textPane.getText()
-							+ "\nCould not send to server. " + e1.getMessage());
+							+ "Could not send to server. " + e1.getMessage()
+							+ "\n");
+				} catch (IllegalArgumentException e1) {
+					textPane.setText(textPane.getText() + e1.getMessage()
+							+ "\n");
 				}
 			}
 		});
 		btnPush.addActionListener(new ActionListener() {
 			public void actionPerformed(ActionEvent arg0) {
 				try {
-					String host = txtHost.getText();
-					int port = Integer.valueOf(txtPort.getText());
-					client.push(userinput.getText(), host, port);
+					if (!txtMsg.getText().isEmpty()) {
+						String host = txtHost.getText();
+						int port = Integer.valueOf(txtPort.getText());
+						client.push(txtMsg.getText(), host, port);
+						textPane.setText(textPane.getText() + "Pushed: "
+								+ txtMsg.getText() + "\n");
+					} else {
+						textPane.setText(textPane.getText()
+								+ "Please enter a message.\n");
+					}
+
 				} catch (NumberFormatException e1) {
 					textPane.setText(textPane.getText()
 							+ "\nErroneous port number. " + e1.getMessage());
 				} catch (IOException e1) {
 					textPane.setText(textPane.getText()
-							+ "\nCould not send to server. " + e1.getMessage());
+							+ "Could not send to server. " + e1.getMessage()
+							+ "\n");
 				} catch (TimeoutException e) {
-					textPane.setText(textPane.getText() + "\nServer timed out."
-							+ e.getMessage());
+					textPane.setText(textPane.getText() + "Server timed out."
+							+ e.getMessage() + "\n");
+				} catch (IllegalArgumentException e) {
+					textPane.setText(textPane.getText() + e.getMessage() + "\n");
 				}
 			}
 		});
diff --git a/ws2012/P2P/uebungen/2/p2p_ex2/src/server/BufferedNetworkStack.java b/ws2012/P2P/uebungen/2/p2p_ex2/src/server/BufferedNetworkStack.java
index c061dae9..762d89e8 100644
--- a/ws2012/P2P/uebungen/2/p2p_ex2/src/server/BufferedNetworkStack.java
+++ b/ws2012/P2P/uebungen/2/p2p_ex2/src/server/BufferedNetworkStack.java
@@ -144,7 +144,12 @@ public class BufferedNetworkStack {
 					break;
 
 				case MessageType.CMD_PRINT:
-					System.out.println(BufferedNetworkStack.this.toString());
+					if (stack.isEmpty()) {
+						System.out.println("Stack is empty");
+					} else {
+						System.out
+								.println(BufferedNetworkStack.this.toString());
+					}
 					break;
 
 				default: