java networking

[hari vallabh shukla]

i have try to get mac address(physical address ) with below code

Inet Address ip=InetAddress.getLocalHost();
NetworkInterface networkInterface= NetworkInterface.getByInetAddress(ip);
byte[] byteNetwork=networkInterface.getHardwareAddress();

but everytime i run program it give different address and when internet connection has lost it give mac address is NULL .I think mac address is physical address so

it should not change, so how can i get mac address(physical address)

[Winston Gutkowski]

hari shukla wrote:it should not change, so how can i get mac address(physical address)

I'm way out of my depth here, but if it was me, my first thought would be that you're not allowed to get the mac address; and, in good "protection" mode, it doesn't tell you that - it simply returns something you can't use.

However, I've never tried what what you're doing, I'm simply guessing. It's certainly what I'd do if I was the security admin on that machine.

Winston

[hari vallabh shukla]

Can we get mac address(physical address) of local machine through java

[Henry Wong]

hari shukla wrote: i have try to get mac address(physical address ) with below code

Inet Address ip=InetAddress.getLocalHost();
NetworkInterface networkInterface= NetworkInterface.getByInetAddress(ip);
byte[] byteNetwork=networkInterface.getHardwareAddress();

but everytime i run program it give different address and when internet connection has lost it give mac address is NULL .I think mac address is physical address so

it should not change, so how can i get mac address(physical address)

It works fine for me. I ran it about twenty times, and I got the same MAC address (for the same NIC) every time.

I was unable to get a null for the MAC address, but I did noticed that when all the NICs were disabled, you get the loopback address as the ip address (which makes sense, as the loopback is the only usable interface). And the loopback interface isn't a hardware NIC, so it doesn't have a MAC address. For the loopback, I noticed that it returned a zero length address as the MAC address.

Henry

[Henry Wong]

Winston Gutkowski wrote:
I'm way out of my depth here, but if it was me, my first thought would be that you're not allowed to get the mac address; and, in good "protection" mode, it doesn't tell you that - it simply returns something you can't use.

However, I've never tried what what you're doing, I'm simply guessing. It's certainly what I'd do if I was the security admin on that machine.

According to the javadoc for the NetworkInterface class, it is supposed to return null, if the caller doesn't have permission to access the MAC address.

Henry