DNS - Domain Name System

• Most overlooked part of the internet
• Without DNS the internet would collapse
• DNS translates a name into the numbers that are the IP address of the desired destination

How does DNS work?

1. A URL is entered

• At the end of the URL such as www.google.com there is another dot "." that the user does not see
• This dot is the root of the internets namespace

2. The browser and operating system will first determine if they know the destination IP address

• The address could be configured on the computer or stored in the cache

3. The browser asks the operating system and neither know the IP address
4. The operating system asks a resolving name server for IP address that it does not know

• The resolving name server is the main part of DNS which is either configured manually or automatically

5. The revolving name server then asks the root server if it nows the IP address
6. If not the root server knows where to find the com servers

• com servers are the TLD servers or Top Level Domain

7. The resolving name server takes all the given information and goes to the com TLD serves
8. The com TLD servers direct the resolving name server to the .com servers such as google.com

• The next servers are called the authoritative name servers or ANSNSO

9. The resolving name server then goes to the .com serves or ANSNSO
10. The ANSNSO then gives the resolving name server the IP address
11. The resolving name server then directs the operating system to the right IP address
12. The operating system gives that IP address to the browser
13. The browser then makes the connection to the IP address for that page