Unique computer ID using MAC.

I need to uniquely identify a computer, and MAC address is the best option i could find.
I am very new to Java (in fact this is my first project outside of the sample codes from the textbook) and cannot think of a good solution to this.

I came up with this code that gets the MAC addresses for the NICs, and it does the job for the most part except on Windows, especially Vista, where it returns 3 addresses out of somewhere when the computer has only 1 NIC.   On linux it works just fine (no surprises there).
Vista gives me:
00 06 4f 5c e8 8f
02 00 54 55 4e 01
00 00 00 00 00 00 00 e0

where only the first one is the real interface.  Also, if i have 2 NICs, then there is another IPv6 address pops up making a total of 5 addresses.

So how can i modify this code so that i get only real hardware addresses, not something made up by the OS.
The emphasis goes on "real hardware" address because i have XP with VMware on it and VMware adapters also show up (and i don't think they are randomly generated).  I doubt this is possible though, but cannot think of a workaround.

Thank you.
import java.io.*;
import java.net.*;
import java.util.*;
 
public class MacAddress {
   public static void main (String args[]) throws SocketException
   {
      byte[] macAddress;
      Enumeration<NetworkInterface> nets = NetworkInterface.getNetworkInterfaces();
      for (NetworkInterface netint : Collections.list(nets)){
         macAddress = netint.getHardwareAddress();
         StringBuilder mac = new StringBuilder();
         if (macAddress != null){
            for (byte b : macAddress){
               mac.append(String.format("%1$02X ", b));
            }
         }
      System.out.println(mac);
      }
   }
}

Open in new window

LVL 11
AlexanderREnterprise Web DeveloperAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Kevin CrossChief Technology OfficerCommented:
You can use:

netint.getDisplayName()

This will give you the name of the interface that the MAC address is being generated for and then you can weed out the ones that you want.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Kevin CrossChief Technology OfficerCommented:
You can also use netint.isUp() to limit the list to only the active connections.  A couple of the tunnel interfaces still show up, but can see what they are using the display name.
0
AlexanderREnterprise Web DeveloperAuthor Commented:
>>weed out the ones that you want.

Not really an option.  This is a Java Applet that verifies uniqueness of user identity on a survey, so its going to go all over the place and i cannot take a chance in guessing all the names of interfaces out there that i may want to include or not.

But this brings me to another idea which is somewhat based on your suggestion.  If i get a list of all virtual OUIs, then i can just compare the first 6 digits against that list.  The applet communicates with a PHP page.  That page can do the job of filtering out "bad" MACs.
0
Kevin CrossChief Technology OfficerCommented:
Good idea and good luck!
0
AlexanderREnterprise Web DeveloperAuthor Commented:
Thanks, I can apply this principle to MAC addresses instead, once i collect a comprehensive list.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Java

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.