Time
60 hours 39 minutes
Difficulty
Beginner
CEU/CPE
40

Video Description

Specific functions of the DNS Server This lesson covers specific functions of the DNS server. The DNS server performs the following functions: - Resolution: performs look ups from Fully Qualified Domain Names (FQDN) to IP addresses and vice versa - Dynamic Domain Name Systems (DNS): Auto update records, monitors changes, may not give everyone permission.

Video Transcription

00:04
So what are some of the more specific functions that are D. N s server performs? Well, let's take a look.
00:09
So our d n a server, as we mentioned, performs resolution. Now our resolution goes two ways. It goes fully qualified domain name to our I p address and these air known as Ford look ups. And then we have I p address to fully qualified domain name reverse lookups Forward lookups are our typical look ups. When we type in
00:29
www dot cyber dot i t
00:31
and it
00:33
ghost or D. N s server are dina server goes to our Internet dina server. And then that being a server says, Okay, that address is at this I p address reverse lookups are if we typed in. Oh, what is this I, p address? What's its server name?
00:49
And then we'll go out to that Dina Dian s server and it'll check its records and see if it has a reverse record
00:56
pointer record and see if it can find its I p address from the fully qualified domain name.
01:03
So our resolution occurs at using our full equality, qualified domain names starting at our top level domains now our top level domains, as we talked about a little earlier include things like dot com
01:15
that in you
01:18
dot gov
01:19
dot mil
01:22
dot or ge
01:23
and so on. And so on
01:26
dot or ge not dot ward
01:30
so so on and so on.
01:33
And these air read right to left. So if you wanted to go to
01:38
portal dot Microsoft dot com
01:41
rd Neff server doesn't read your request from left to right, it needs to start
01:47
from right to left.
01:48
So you may see website addresses
01:52
that look like this. Http colon Ford's last forward slash w w w dot portal dot Microsoft dot com slash log in. So let's take a look at this and see if we can get rid of some of the extra stuff.
02:07
So
02:07
http www dot portal dot Microsoft dot com forward slash log in.
02:12
Well, immediately we can remove this ford Slash are actually start from this side.
02:19
Http. Colon forward slash forward slash
02:23
Is just telling our computer what's protocol to use. We're gonna use http protocol in order to connect to this website because http is what's goingto let us to let us connect to our website. Let us pull information from a website,
02:38
so that's not part of our d. N s query. That's just part of our computer specifying which protocol it's going to use. So that's not part of our d. N s query
02:50
W W W.
02:53
As part of our is the start of our d. N s query, but our www means that we are asking the server to give us it. Give us its worldwide Web page. That's why a lot of times you could just type in portal dot Microsoft dot com,
03:07
and then our browser will fill in the rest because it's assuming that we're goingto want to go to
03:13
the World Wide Web page, the World Wide Web page on this server. So are our www server, whichever we have configured. So we're telling our computer, Yeah, we want to go to the Www Server, the World Wide Web server
03:28
So
03:30
www dot portal dot Microsoft dot com.
03:35
The rest of this is part of our query as well, because that's part of our domain. Microsoft Microsoft, part of our domain dot com, is a root domain. And then what about this ford slash log in Well, that forward slash log in. We can also is also not part of our dean s query, because that fourth slash log in
03:53
is simply asking for an additional
03:58
sub folder or sub file with on this Web server. So if you think about a file path, if you're going to you're a certain file on your computer, you'll see something something like, uh, see ford slash You'll see backslash backslash see ford slash
04:17
users ford slash administrator ford slash desktop So we're essentially going to the server and saying I want to go to your main Web server. Ford slash your log in page So that's not part of our d. N s query our d n a square. He just wants to find the i p address
04:34
of this server, the www dot portal about Microsoft dot com server.
04:39
So we're gonna start from left are from right to left of this as we're resolving.
04:44
So this was just us dissecting it.
04:46
So our computer is going to say our initial our initial the internal DNF server is going to say, OK, I don't know where this query is, so I'm going to send it up to the next level D and s
04:59
now next level D. N s on our Internet is going to say, OK,
05:02
I need to find the server. Who knows where who has the authority to tell me
05:11
information about the dot com domain. So it says, Okay, I know. I know which Dina server was allowed to tell me about the dot com D. N s are the dot com domain,
05:23
and then we need to know who can tell us about the dot Microsoft sub domain.
05:29
So our dot com domain is our route domain that is encompassing of all of our Web sites and servers that are something dot com.
05:39
So we find the one that can tell us information about that when we say Okay, now, where is the next the next? Level up, the dot Microsoft domain and we say, Okay, here it is. Now where is the Microsoft? Are the portal dot Microsoft
05:57
domain. So then we find that, and then once we're there, once were at whichever server can tell us about the portal dot Microsoft dot com domain, we say, Okay, now where's your Web server? Where's your www server? And then it gives us the I P address.
06:12
And then now our computer sends an http packet
06:15
to that to that i p address requesting it's log in page.
06:21
So that's how I r u r l will translate into our d. N s request.
06:27
Now, our Deanna servers can provide us with dynamic VMS. Now, dynamic Dean s
06:32
versus a static would be a auto updating of our records.
06:38
Our d. N s records are going to be the information inside of our guardian s servers that's configured with what goes where the information to allow us to resolve fully qualified domain names to R I P addresses and the reverse
06:50
our dynamic D N s will automatically update those records so we don't have to manually change things.
06:56
And our dynamic Dean s will monitor changes in assisting in connection with D h C P s o D A. C P hands out, at least to a particular server, our particular computer. It lets our D. N s know in our D. N s will update those records now,
07:13
and our domain environment we need We don't necessarily want
07:17
all the computers that connect to our domain to be able to allow them to update D N s for, um,
07:25
for the computers. Well, why not? Why don't We don't want to allow our client computers the ability to update D N s. Well, if we give them that ability to every single client computer, we may have a client computer that says, Oh, hey, D n s. By the way, I want you to add this record in here. I want you to add in here that www dot facebook dot com
07:45
points back to me.
07:47
So if that record is maliciously added, then someone could stand up a little client computer with a fake Web server on it. And then when we add that record and our d. N s says, Oh, you requested W w w w dot facebook dot com Here is this I. P address sends us to the client computer
08:07
that has a completely
08:09
constructed fake look alike of facebook dot com. You enter in your user name and password in and the U. R L. Barr says www dot facebook dot com. It looks completely fine, but then your information is being transmitted to that computer that you act you actually connected to.
08:28
So our D. N s server once it tells us Oh, yeah, this I p addresses facebook dot com our computer will say Okay, well, I'll go there and then in our u R L Bar will display that were connected to facebook dot com because that's what our Deena's told us that we're connected to. Its not gonna connect the I P address.
08:45
It's not going to show with the I. P address of the server that we're connected to
08:48
on our standard browser UL bar. It's just gonna So what? What address it thinks it's connected to.
08:54
That's why it's important to keep our d. N s secure
08:56
and keep our d. N s from being updated maliciously.

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