DNS Explained

Uploaded by DNSMadeEasy on 27.02.2012

Today, there are people trying to dictate how the Domain Name System-known as DNS by the cool kids,
and by association, the Internet as a whole, works.
Unfortunately, many of these powerful individuals, and others, don’t understand what exactly DNS is.
This video is for them and for anyone else that wants to learn about DNS.
We are going to go over the basics of what DNS is, how it works, and how if you use the Internet, it affects your life daily.
Think you know what DNS is already? Stick around anyway, you might learn something.
Here at DNS Made Easy we love DNS and could obviously spend hours going into each and every detail, but we’re only explaining the basics here.
If you ever decide to run for public office someday and want to make decisions on DNS… This will help.
OK… let’s begin.
The Domain Name System is indisputably one of the most important and over-looked parts of the Internet.
Without DNS, the Internet as we know it today, would collapse, and we would all be licking stamps to pay our bills,
driving to an actual store to purchase something, reading the newspaper to see what movies were showing,
or buying little round pieces of plastic called CDs to get our music.
How can we say that DNS is this important?
We all know (or should know), that the computers that make up the Internet are set up in large networks that communicate with
eachother via underground (or under water), wires and are identified using strings of numbers known as IP addresses.
Since the majority of us lack the mental capacity to sort through and retain hundreds of numerical series,
DNS is used to translate an actual name into these numbers. But how does the Domain Name System work?
In a web browser let’s say you enter the URL, www.example.com as a… well, as an example.
When you type www.example.com into your address bar, you will actually be looking for www.example.com..
Yes there is a dot at the end of the domain name. One that you never see. And one that you never type.
When you type in www.google.com, you are actually going to the page www.google.com.. Seriously. Try it out, we’ll wait.
(crickets chirp)
Ok look, that's long enough…
Anyway that end dot represents the root of the Internet’s name space.The Root!
Why is this so important? Because this is where it all begins.
When you first search for www.example.com.,
your browser and your operating system will first determine if they know what the IP address is already.
It could be configured on your computer or it could be in memory, what the cool kids call cache. No, not cash as in cash money;
the memory cache, C-A-C-H-E. Keep up, will ya?! Anyway...
So the browser asks the operating system and they both don’t know where www.example.com. is. What happens next?
The operating system is configured to ask a resolving name server, for IP addresses is does not know.
This resolving name server is the workhorse of the DNS lookup. It is either configured manually or automatically within your operating system.
Your operating system asks (or queries), the resolving name server for www.example.com..
The resolving name server may or may not have this in memory or, you know, cache. Yes the C-A-C-H-E one, not the... nevermind.
For the sake of this demonstration, it does not.
The only thing that all resolving name servers should know, is where to find the root name servers.
Yes, that enigmatic dot that appears at the end of every domain name you type into that address bar.
The root name servers will reply with “I don’t know, But I do know where to find the com name servers. Try there.”
The COM name servers are called the Top Level Domain name servers or TLD name servers.
The resolving name server then takes all of this information from the root name servers,
puts it in its cache, and then goes directly to the COM TLD name servers.
When the resolving name server queries www.example.com, the TLD name servers respond,
“I don’t know, but I do know where to find the “Example.com” name servers. Try there.”
This next set of name servers are the authoritative name servers.
So how did the COM TLD name servers know which authoritative name servers to use?
With the help of the domain’s registrar.
When a domain is purchased, the registrar is told which authoritative name servers that domain should use.
They notify the organization responsible for the top level domain (the registry), and tell them to update the TLD name servers.
So… anyway…
The resolving name server takes the response from the TLD name server, stores it in cache, and then queries the example.com name servers.
At this point, the authoritative name server will say, “Hey! I know where that is! Tell your browser to go to the IP Address!
The resolving name server takes this information from the authoritative name server, puts it in cache,
and gives the reply to the operating system. The operating system then gives this to the browser
and the browser then makes a connection to the IP address requesting the web page for www.example.com.
Pretty cool huh?
While the process seems complex-and, believe me it is, this whole cycle take less time than it takes you to blink an eye.
DNS was designed to work extremely fast and efficiently. It is an integral part of the Internet.
Once you understand this, you can clearly see the many different facets and organizations that are responsible for a single DNS lookup.
One lookup!
There is a resolving name server, the root name server, the TLD name servers, and the authoritative name servers.
If anyone were to dramatically change or filter any part of the DNS process, it could lead to disaster.
This is why we believe the people with the power to pass legislation need to understand what’s at stake before making decisions that
could drastically affect how the Internet works!
If you want to learn more about DNS, and see the DNS process in action first hand, type www.dnsmadeeasy.com into your browser.
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