Domain Name System
Let's imagine you want to research additional information about the Cisco Certified Network Associate (CCNA) certification. The best place to start researching would be Cisco's website at www.cisco.com. Open your favorite web browser and simply enter the URL into the address bar and hit Enter. After a few seconds, the Cisco website appears and you can continue your research. Everything seems to work like magic, but have you ever wondered how your computer determines the IP address for the web server that is hosting Cisco's website?
As mentioned in Chapter 3, IP Addressing and Subnetting, each device that is connected and exchanging messages on a computer-based network must be assigned a unique IPv4 or IPv6 address. The same is also applied to all devices on the internet, such as web and mail exchange servers. If a web server is identified by its IP address, why does it have a website URL address such as www.cisco.com?
To help you understand the...