How to get uuid or mac address from client in Java?

Question

I'm looking for a solution for a Java based webapplication to uniquely identify the client. The server is in the same network as the clients and I thought that using the MAC address would be a good solution. The problem is I can't work with cookies because they can be deleted client-side and I can't use the IP because they could just issue a new DHCP lease renewal.

So I would like to fallback to the MAC address of the clients. I'm aware that there is no java built in feature to get the MAC address. Is there a library that can handle the output of every OS? (primary Windows and Mac) since my java Application runs on both platforms.

or are there any other suggestions for uniquely identifying a client within a website and the HTTP Protocol ? (maybe HTML5 data stores or something else)

I'm using Java 1.7 btw.

I won't force the user to login or otherwise identify himself and I won't program a native app for the clients smartphone.

Answer 1

I wrote my own method to solve my issue. Here it is if ever someone needs code to find a MAC address in the same network. Works for me without any admin privileges on Win 7 and Mac OS X 10.8.2

Pattern macpt = null;

private String getMac(String ip) {

    // Find OS and set command according to OS
    String OS = System.getProperty("os.name").toLowerCase();

    String[] cmd;
    if (OS.contains("win")) {
        // Windows
        macpt = Pattern
                .compile("[0-9a-f]+-[0-9a-f]+-[0-9a-f]+-[0-9a-f]+-[0-9a-f]+-[0-9a-f]+");
        String[] a = { "arp", "-a", ip };
        cmd = a;
    } else {
        // Mac OS X, Linux
        macpt = Pattern
                .compile("[0-9a-f]+:[0-9a-f]+:[0-9a-f]+:[0-9a-f]+:[0-9a-f]+:[0-9a-f]+");
        String[] a = { "arp", ip };
        cmd = a;
    }

    try {
        // Run command
        Process p = Runtime.getRuntime().exec(cmd);
        p.waitFor();
        // read output with BufferedReader
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                p.getInputStream()));
        String line = reader.readLine();

        // Loop trough lines
        while (line != null) {
            Matcher m = macpt.matcher(line);

            // when Matcher finds a Line then return it as result
            if (m.find()) {
                System.out.println("Found");
                System.out.println("MAC: " + m.group(0));
                return m.group(0);
            }

            line = reader.readLine();
        }

    } catch (IOException e1) {
        e1.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    // Return empty string if no MAC is found
    return "";
}

Answer 2

The best I could find is this: Query ARP cache to get MAC ID

And the potted summary is that:

• there is no standard Java API,
• there is no operating system independent solution,
• your application typically needs to be privileged (eg root access) to query the host's ARP cache, and
• if the packets go through a network router, you won't be able to identify the source MAC address anymore.

I don't think this is a good approach for identifying your user's machine.

Consider also that:

• This only identifies the machine, not the user. Some computers are shared by multiple users.
• MAC addresses can be changed too.

Answer 3

Usage of IP address isn't working in the local network . I have used some other method to get a MAC address - sysout parsing of useful commands.

public String getMacAddress() throws Exception {
    String macAddress = null;
    String command = "ifconfig";

    String osName = System.getProperty("os.name");
    System.out.println("Operating System is " + osName);

    if (osName.startsWith("Windows")) {
        command = "ipconfig /all";
    } else if (osName.startsWith("Linux") || osName.startsWith("Mac") || osName.startsWith("HP-UX")
            || osName.startsWith("NeXTStep") || osName.startsWith("Solaris") || osName.startsWith("SunOS")
            || osName.startsWith("FreeBSD") || osName.startsWith("NetBSD")) {
        command = "ifconfig -a";
    } else if (osName.startsWith("OpenBSD")) {
        command = "netstat -in";
    } else if (osName.startsWith("IRIX") || osName.startsWith("AIX") || osName.startsWith("Tru64")) {
        command = "netstat -ia";
    } else if (osName.startsWith("Caldera") || osName.startsWith("UnixWare") || osName.startsWith("OpenUNIX")) {
        command = "ndstat";
    } else {// Note: Unsupported system.
        throw new Exception("The current operating system '" + osName + "' is not supported.");
    }

    Process pid = Runtime.getRuntime().exec(command);
    BufferedReader in = new BufferedReader(new InputStreamReader(pid.getInputStream()));
    Pattern p = Pattern.compile("([\\w]{1,2}(-|:)){5}[\\w]{1,2}");
    while (true) {
        String line = in.readLine();
        System.out.println("line " + line);
        if (line == null)
            break;

        Matcher m = p.matcher(line);
        if (m.find()) {
            macAddress = m.group();
            break;
        }
    }
    in.close();
    return macAddress;
}

This should work everywhere. At least, the usage of this method on Ubuntu machine gives the following result:

Operating System is Linux
line eth0      Link encap:Ethernet  HWaddr f4:6d:04:63:8e:21  
mac: f4:6d:04:63:8e:21