If you are connected to the Columbia University network, you can use this script to determine your IP and MAC addresses.
On Windows operating systems, you can determine your IP and MAC addresses by opening a command prompt windows (Start -> Run -> cmd) and typing ipconfig /all. Look for the value of IP Address to determine your IP address and Physical Address to determine your MAC.
For Macintosh OS X, open a Terminal window and type ifconfig -a. Look for the value of ether.