====== Network Scanner ======
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===== Description =====

Network Scanner is a Java application that provides a graphical user interface for scanning the local network and performing basic network operations such as ping and nslookup.

===== Features =====

  * Scan local network to find active IP addresses
  * Perform ping on a selected IP address
  * Perform nslookup on a selected IP address
  * Intuitive Windows-style graphical interface

===== System Requirements =====

  * Java Runtime Environment (JRE) 8 or later
  * Windows operating system (for native Windows look and feel)

===== Installation =====

  - Download the application JAR file
  - Ensure you have JRE installed
  - Double-click the JAR file to run the application

===== Usage =====

  - Launch the application
  - The list of IP addresses from the local network will be automatically displayed
  - Select an IP address from the list
  - Click the "Ping Selected IP" button to perform a ping
  - Click the "NSLookup Selected IP" button to perform an nslookup
  - Results will be displayed in a separate window

===== Source Code =====

<code java NetworkScannerApp.java>
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class NetworkScannerApp extends JFrame {
    private JList<String> ipList;
    private JProgressBar progressBar;
    private JButton pingButton;
    private JButton nslookupButton;
    private JPanel contentPane;

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch (Exception e) {
            e.printStackTrace();
        }

        EventQueue.invokeLater(() -> {
            try {
                NetworkScannerApp frame = new NetworkScannerApp();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
    }

    public NetworkScannerApp() {
        setTitle("Network Scanner");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(new BorderLayout(0, 0));

        JPanel topPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
        topPanel.add(new JLabel("IP Addresses:"));
        contentPane.add(topPanel, BorderLayout.NORTH);

        List<String> ipAddresses = getIpAddresses();
        ipList = new JList<>(ipAddresses.toArray(new String[0]));
        ipList.setBorder(BorderFactory.createLineBorder(Color.GRAY));
        JScrollPane scrollPane = new JScrollPane(ipList);
        contentPane.add(scrollPane, BorderLayout.CENTER);

        JPanel bottomPanel = new JPanel();
        bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.Y_AXIS));

        progressBar = new JProgressBar();
        progressBar.setIndeterminate(true);
        progressBar.setVisible(false);
        bottomPanel.add(progressBar);

        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));
        
        pingButton = new JButton("Ping Selected IP");
        pingButton.addActionListener(e -> {
            String selectedIp = ipList.getSelectedValue();
            if (selectedIp != null) {
                startProcess(selectedIp, "ping");
            } else {
                showErrorDialog();
            }
        });
        buttonPanel.add(pingButton);

        nslookupButton = new JButton("NSLookup Selected IP");
        nslookupButton.addActionListener(e -> {
            String selectedIp = ipList.getSelectedValue();
            if (selectedIp != null) {
                startProcess(selectedIp, "nslookup");
            } else {
                showErrorDialog();
            }
        });
        buttonPanel.add(nslookupButton);

        bottomPanel.add(buttonPanel);
        bottomPanel.add(Box.createRigidArea(new Dimension(0, 5)));

        contentPane.add(bottomPanel, BorderLayout.SOUTH);
    }

    private List<String> getIpAddresses() {
        List<String> ipAddresses = new ArrayList<>();
        String command = "arp -a";
        try {
            Process process = Runtime.getRuntime().exec(command);
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line;

            while ((line = reader.readLine()) != null) {
                String[] tokens = line.split("\\\\s+");
                for (String token : tokens) {
                    if (token.matches("\\\\d+\\\\.\\\\d+\\\\.\\\\d+\\\\.\\\\d+")) {
                        ipAddresses.add(token);
                    }
                }
            }
            process.waitFor();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return ipAddresses;
    }

    private void startProcess(String ip, String command) {
        progressBar.setVisible(true);
        pingButton.setEnabled(false);
        nslookupButton.setEnabled(false);
        SwingWorker<String, Void> worker = new SwingWorker<String, Void>() {
            @Override
            protected String doInBackground() throws Exception {
                if ("ping".equals(command)) {
                    return pingHost(ip);
                } else {
                    return nslookupHost(ip);
                }
            }

            @Override
            protected void done() {
                try {
                    String result = get();
                    showResultDialog(ip, result, command);
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    progressBar.setVisible(false);
                    pingButton.setEnabled(true);
                    nslookupButton.setEnabled(true);
                }
            }
        };
        worker.execute();
    }

    private String pingHost(String ip) {
        return executeCommand("ping -n 4 " + ip);  // Limit to 4 packets for Windows
    }

    private String nslookupHost(String ip) {
        return executeCommand("nslookup " + ip);
    }

    private String executeCommand(String command) {
        StringBuilder result = new StringBuilder();
        try {
            Process process = Runtime.getRuntime().exec(command);
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line;
            while ((line = reader.readLine()) != null) {
                result.append(line).append("\\n");
            }
            process.waitFor();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result.toString();
    }

    private void showResultDialog(String ip, String result, String command) {
        JDialog dialog = new JDialog(this, command.toUpperCase() + " Result for " + ip, true);
        dialog.setSize(400, 300);
        dialog.setLocationRelativeTo(this);

        JTextArea textArea = new JTextArea(result);
        textArea.setEditable(false);
        textArea.setFont(new Font("Consolas", Font.PLAIN, 12));
        JScrollPane scrollPane = new JScrollPane(textArea);
        dialog.add(scrollPane);

        JButton closeButton = new JButton("Close");
        closeButton.addActionListener(e -> dialog.dispose());

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(closeButton);
        dialog.add(buttonPanel, BorderLayout.SOUTH);

        dialog.setVisible(true);
    }

    private void showErrorDialog() {
        JOptionPane.showMessageDialog(this, 
            "Please select an IP address.", "Error", JOptionPane.ERROR_MESSAGE);
    }
}
</code>

===== Troubleshooting =====

If you encounter issues:

  * Make sure you're running the application with administrator rights
  * Check if your firewall is not blocking the application
  * Ensure you have the necessary permissions to execute network commands