Each electronic device conected to Internet must have IP as an identifier in the network. IP (Internet Protocol) is a unique number to identify and communicate with each other on a computer network utilizing the Internet Protocol standard.

When you conect to internet, you get a IP address. This address can change when reconect; then this is a dynamic IP address.

Websites in Internet that need to be conect all the time , use a Static IP address, this ip address don't change. Dynamic or Static IP address acts as a locator. Computers can use IP to find address, people must use something easy like URLs (for example: http://www.niponcomputer.com).