This is part of the book "Introduction to Networking" at www.net-intro.com
The Domain Name System lets you access websites by their domain name like (www.net-intro.com), so you don't have to keep a list of numeric Internet Protocol (IP) addresses like "22.214.171.124". IP address are determined by *where* your computer connects to the Internet. When you have a portable computer and you move from one location to another, you get a new IP address at each new location. Since no one connects to your portable computer, it does not matter if your IP address changes from time to time. But since so many people connect to a web server, it would be inconvenient if the server moved to a new location and needed to change its IP address.