I have no idea what they're talking about.
IP however is short for internet protocol. IPs usually refer to IP addresses, which is the number of your computer when on a network.
analogy gun...fire:
It's your house number. On a very big street. Whenever you visit a site, you ask the computer at the site's house number to send you a page. They send the webpage back to you to your house number.
Banning works in this way, you ignore the messages from certain house numbers.
It isn't really possible to change your IP address, but it is possible to make your messages come from a different address. You go to a friend's house or get someone to send on behalf of you.
You can find out your IP by going to sites like these:
ip-adress.com.