You remember names. Machines only understand numbers. DNS is the address book that turns names into numbers.
It's like tapping "Mom" on your phone to call her. You never have to memorize her number.
2
What if it didn't exist?
WITHOUT IT
To visit any website, you'd have to memorize a string of a dozen or so digits
Like having to look up the phone book before every call, and the number changes whenever the other person moves.
WITH IT
Type a name and you're there
A changed number doesn't matter: update the address book, and you keep using the name.
Put simply: names are for people, numbers are for machines, and DNS translates in between.
3
How does it look things up?
1. Check your own notepadFor a site you just visited, your phone already remembers the number and uses it directly
2. Ask "directory assistance"Not in your notepad? Ask the directory service run by your internet provider
3. It asks level by levelFirst the main desk ("who runs .com?"), then that company, and finally the website itself
4. Get the number, remember it for a whileConnect; copy the number into your notepad so you needn't ask next time
The whole loop usually takes less than the blink of an eye.
4
What it does all day
Every time you open somethingWatching videos, browsing, sending messages: it looks it up first
Websites can move without you knowingNew machine? Just update the address book
Points you to the nearest oneBig sites have many branches, and it gives you the number of the closest
Which mailbox gets your emailBefore a letter is sent, it checks here first
You use it thousands of times a day, and have never seen it once.
5
What it handles, and what it doesn't
It only looks up numbers, and stores no web contentIt tells you "where to go," but what you see when you arrive has nothing to do with it. Just as an address book doesn't know what you said on the phone.
A changed number isn't known worldwide at once.Everyone's notepad still holds the old number, and it takes a while before they ask again. So right after a website moves, some people can open it and others can't.
If someone tampers with the address book, you get sent to the wrong place.The name is right, but the number was swapped for a fake one. That's why you should look for the little padlock in the address bar.
"What does this have to do with me?"
Next time a website won't open while your messaging apps still work fine, don't rush to say "the website is broken." It may well be directory assistance getting stuck.
If switching networks (turn off Wi-Fi and use mobile data) fixes it right away, it's most likely this.
