I am in Cisco Networking Academy with my college we just went over Networking securities, your computer is assigned 1. A MAC address which is like your thumbprint it never changes. 2. Your computer has an IP address which is like your house address. it can change. If your are curious about your own address open up the command line and type in ping /all and it will give you all the info on your address, or your can ping an address by entering in (example)ping
www.yahoo.com and it will send a ping to the address and echo request back. But IP addresses can change and you can go into your settings and reassign one as well. But the MAC address is in your NIC card and its there permanent
Vanpet
In my own opinion for a person to hack into CA's account and email the contents there had to be some incriminating substance in the emails. I cannot see someone taking a chance at a criminal charge over bs. the first ***.***.** numbers in the ip address are assigned to the isp (example) 196. would be like comcast