What is DNS? (part 1)

Video Activity

What is DNS? This lesson introduces Domain Name Services (DNS). DNS allows us to resolve Fully Qualified Domain Names (FQDNs) to an IP address. An FQDN is the name of a server, web site or device that we can access on the network. DNS consists of two components: - The client: receives the request - The server: answers the request

Join over 3 million cybersecurity professionals advancing their career
Sign up with
or

Already have an account? Sign In »

Time
31 hours 29 minutes
Difficulty
Beginner
CEU/CPE
30
Video Description

What is DNS? This lesson introduces Domain Name Services (DNS). DNS allows us to resolve Fully Qualified Domain Names (FQDNs) to an IP address. An FQDN is the name of a server, web site or device that we can access on the network. DNS consists of two components: - The client: receives the request - The server: answers the request

Video Transcription
00:04
Hi and welcome to cyber dot i t.
00:06
My name's Anthony and I'm your local subject matter expert here for networking Plus And today we're gonna talk about our concepts and components of D. N s. What is D N s? What is D n s Do and how does it do it?
00:19
Well, we've talked about D n s a little bit in previous modules, just sort of in passing. We talked a little bit about what it does, but this module, we're gonna really dive into it and really see what it does and how it does what it does. So
00:33
what is D. N s? Well, D N s is actually an acronym that stands for domain name service. Now, domain name service is what allows us to resolve F. Q. Tien's also known as fully qualified domain names to an I. P. Address. Well, what is a fully qualified domain name?
00:53
Well, a fully qualified domain name
00:55
is a name of a server website device that we can access on the network.
01:03
Now, these four qualified domain names have to be more than just the computer name. We not only need to know the computer name We also need to know what additional additional information like what domain is our computer on is our computer on if we have a server that we're trying to reach and we just type in Google
01:23
in our U. R L
01:23
well, we can't just not navigate to Google. We need tohave a dot com after that, because Google is a particular, it's a particular place on the dot com domain,
01:38
so
01:40
let's talk about domains a little bit.
01:42
So a domain
01:45
is essentially a a grouping of computers that are under this same sort of control.
01:53
Um, we break up different domains into smaller sub domains by adding on additional dots and adding on additional locations.
02:00
So when we take a when we take a Web address,
02:06
we take a Web address like
02:07
w W w dot
02:10
google
02:12
dot com.
02:15
Well, we're reading a Web address
02:17
instead of reading it from left to right. Let's read it from right to left.
02:23
Our first
02:24
dot com
02:27
a dot com is a root domain now. Route domains are domains that can be accessed
02:32
all across the world, and they are the main domains on the Internet. If you want to have a website on a route domain. Or you wanna have a server on a route domain, you're gonna have to register that domain so that it's yours so that nobody else can have it.
02:46
Like if you register pizza dot com, which is already registered, then you'll have to go out and you'll have to actually register that you own and you'll have to pay for pizza dot com.
02:58
Now dot com is one of many root domains
03:02
we have dot coms we have dot edu use. We have dot mills.
03:08
We have different. We have different dot gov sze
03:15
and different countries dot you
03:17
and the list goes on and on now. We've been recently adding more root domains more domains other than just dot com dot edu dot mil dot gov, and you'll see more and more pop up, such as cyber rea dot i t dot i t is now a route domain. So it
03:38
really depends on
03:39
if you have the qualifications number one for purchasing a website or registering a domain within that domain in order to purchase one on purchase one on that route domain.
03:53
So, for example,
03:55
if you were to buy a try to register a dot com domain, then you could just go out and register that domain. There really aren't many anything any stipulations preventing you from doing that? But if you wanted to register a dot mil, you would need special authorization to do that. Because on Lee,
04:13
military organizations can register a dot mil
04:16
domain on the route domain.
04:19
So we have www dot google dot com. Now
04:25
R. W W W
04:28
is essentially saying we're trying to get to the www page work on trying to get to the World Wide Web page on the server. Google dot com.
04:39
So we're trying to access its webs, its Web facing page. You don't have to register a public domain to have a fully qualified domain name.
04:47
If you have a server, which is just out there on your network out there in your domain you have, you may have a domain such as
04:56
a dot local dummy.
04:59
Now it doesn't have to be dot local. It could be dot anything. As long as that dot anything isn't a isn't a route Domain isn't like a dot com or dot edu. You can even hypothetically set up a domain network with a dot com route domain without having to actually go on register one.
05:18
But as soon as you try to put that online and connect out to the Internet,
05:21
things are gonna work very smoothly for you. You're not gonna be able to access. Those people aren't gonna have the right D. N s records in order to get to your servers like you want them to. That's why we have to register them.
05:31
But anyway,
05:33
so if we set up a local domain, we set up a local network of computers that we want to put in a domain. Then we can just set up, say, a cyber domain that we call cyber very dot local. So we have cyberia dot local, and that's our domain. So that's our the name for our group of computers.
05:50
And if we wanted to break that down even further, we could have
05:55
department dot cyberia dot local and on and on and on as some or sub Seymour
06:00
sub domains there for us, we have a fully qualified domain name that I just inadvertently erased. So we have a domain name and now we need to make this a fully qualified domain name. So what? How do we make this a fully qualified domain name? We'll just like when we took a look at www dot google dot com,
06:20
a fully qualified domain name.
06:23
We'll need to have some sort of location that we're going to on that domain.
06:28
If we're just trying to access the cyber dot local domain, then we
06:31
we aren't really using d N s, resulting We're not resolving a server name to an I p address. But if we have a sober on that domain, say if we have a sales server so we have sales, not cyberia dot local On our sale servers where we keep all our sales records,
06:47
then a fully qualified domain name will be something like sales
06:53
dot cyber very dot local.
06:56
So now, if we wanted to go to our sales computer and we typed in navigate to sales dots, I bury got local, then full in our d. N s would take this And what would it do? Well, RG ns would translate that into an I p address for us
07:14
now, it doesn't translate it in the sense of when we translate i p addresses into binary it translates it in the sense that it goes and looks in its records and sees if it knows who
07:26
our sales dots I barely got local is as their i p address.
07:30
So
07:32
we have sales. That's I bury dot local and we need to navigate to the server. Well, our d N s will look in its records and say OK, I have a d. N s entry for sales dot cyber dot local
07:46
as 1 92.1 68.1 dot 17
07:54
and that's the server that is sale starts. I buried out local.
07:58
So why do we have to have the NS? Why can't we just
08:01
connect to a computer with its holy qualified domain name?
08:03
Well, we need d N s because computers have to speak in numbers.
08:09
They have to be able to take numbers and they have to break them down into eventually electrical impulses. So electrical impulses are either on or off.
08:18
So we have our
08:20
electrical impulses here. Well, they have to either be on or off. And
08:26
our computers No, we can't memorize electrical impulse impulse signals, or at least not all the electrical impulse signals We would need in order to translate things into letters and numbers. So we take those electrical impulses and we convert them into by. And those air converted by our computer into binary
08:41
and binary is just ones and zeros. Ones standing for a an electrical signal that's on and zero standing for an electrical signal that's off.
08:54
So
08:56
ones and zeros memorizing the ones and zeros necessary in order to form the asking characters which form the letters, which form
09:03
the name is still bit hard for us. So those ones and zeros
09:09
are used and translated by our computer in tow. I p addresses for us,
09:15
which is great I p addresses or something we can work with. Weaken type those in on the computer a lot faster than we would be able to type out a string of buying area or work with electrical impulses. So we've converted those buying that buying ery into numbers.
09:28
Now think of all the Web sites you visit, possibly even on a daily basis. Think of all the servers at work that you connect to in order to pull your files down and to navigate and browse through the different shared folders if you had to memorize
09:43
the I P address for every single one of those computers, things would be a bit harder
09:48
if you had to know the I p address for Google in order to search for where Facebook was. In order to find its I P address and then click on its I p address and navigate to its I p address, you'd be having a little bit of, ah, tougher time navigating around the Internet.
10:05
So
10:05
we take I p addresses and we can train when we translate those into things that humans can remember easily, which are words
10:15
Now
10:16
computers have two trains like those words back down,
10:18
and that's where Deanna's comes in.
10:20
So we type in the words and then d N s will look in its records and see
10:28
who that word belongs to, like who? That domain and what that computer belongs to it. As far as its numbers go and this number this 1 92.16 th that one that seven we can route with, we can now connect using that number, whereas that word wasn't really helping us as much.
10:45
So we mean we need d n s in order to get to places on the Internet
10:50
and get to places even in our own local domain.
10:52
When it comes to our d. N s, we have two main components. There's a lot of components that go into D. N s, but the two main ones are going to be clients and going to be servers.
11:01
Now a client is our computer, which sins? A request
11:05
in the server is going to be the server that answers the request simple enough.
Up Next
CompTIA Network+

This CompTIA Network+ certification training provides you with the knowledge to begin a career in network administration. This online course teaches the skills needed to create, configure, manage, and troubleshoot wireless and wired networks.

Instructed By