Q: How do I find out what the ethernet/hardware/MAC/physical address of my computer is?

Each network card is assigned a unique address by its manufacturer. It is known as an ethernet or hardware or MAC or physical address, depending on the source, but all these are basically the same.

Such an address has the form xx-xx-xx-xx-xx-xx, where x is hexadecimal, and the first pair is almost always 00 or 08, while the second usually contains a 0. Instead of a dash (-), the separator can sometimes be a column (:).

How to obtain this address depends on the OS. For:

  • MacOS, go to the Apple menu (top left), and select Apple System Profiler. Then, in the System Profile tab (that comes up by default), expand the Network Overview arrow, and then the Apple Talk one. It will show up as hardware address.

  • UNIX, type ifconfig -a (as ``root'') and it should show up under one of the names mentioned above (typically, HWaddr for Linux and ether for SunOS). On our Sun systems, you can type arp -a | egrep SP and it will be the last column.

  • Windows, open a DOS window, and type ipconfig /all. It will be labeled physical address.

  • others, please inquire if you are not sure.
  • Note that this will give you the information for the NIC currently in use. If your computer has multiple interfaces (e.g. wireless and ethernet, or for public and private networks), make sure that you identify the correct one.

    Your system need not be connected to any network in order to find out this information. Please do NOT connect a computer to the UCLA Astronomy network if you have not provided its address to the system administrators beforehand or previously been assigned an IP address.