DNS is the phonebook of the Internet.

When you call your friends on the phone, you pick their name from your contact list and the phone does the rest. The Internet works the same way!

Every website out there, from Amazon to Skillcrush, lives on a web server. This web server has an address out there – an IP address, to be specific – something like 216.172.190.36. By knowing its IP address you can send information to the web server, and say things like “I want that web page!”

The thing is, no one is going to remember 216.172.190.36! They’re just going to remember skillcrush.com. That’s where DNS comes in.

DNS stands for Domain Name System. DNS servers are a whole bunch of computers out on the Internet that keep a record of the domain names and IP addresses of all of the other computers on the internet. So when you want to visit Skillcrush, the first thing your computer does is ask a DNS server for skillcrush.com’s IP address. Once it gets the IP address, it talks directly to the computer at 216.172.190.36 to ask for a web page.

Numbers get into the DNS phonebook when you register a domain name, and it’s your job to keep it updated if you change web servers or IP addresses. Updating your DNS record is like emailing all your friends “I got a new phone, here’s my number.” Except, you are telling a bunch of web servers and it’s not your phone number…on second thought, let’s not push that analogy too hard.

Cocktail Party Fact

When you change a domain name or web server, all the DNS servers on the Internet need some time to update their phonebooks. This is called “propagation delay,” and it can take between 2 – 24 hours. It’s the same as what your friends would have to do if you got a new number!