In this lecture, you will manipulate the domain name system the and.
Hackers can find a treasure trove of information on a target in its domain name system DNS, so DNS
is a critical component of the internet.
So and although it's designed to translate domain names to IP addresses so A. can use it to garner information
on the target.
And Dennis is a service that translates a domain name like, for example.
Let's open their browser, and they will, for example, Google that come to appropriate IP address.
So I will show you an installation of the end this year will come here.
Actually, our internet is disconnected because I log out our.
Network adapter here, and I will fix it now here.
Let's see if I see a doctor go.
Uh, we will.
Conduct a core here, and I will search here the in this, uh.
And I want to show you an illustration here for better understanding.
Uh, so actually.
In this.
War.
Here, as you can see here, the uh, let me open here.
So, um, this is them our possible attacks here.
So first, I want to talk about, uh uh, is, uh, Google here, for example.
Um, it DNS is a service that translates a domain name, uh, for example, like, uh, Google dot com
to IP address.
So the way your system knows how to get to do it, so without Dennis, we will all have to remember
thousands of IP addresses like that.
For example, in Google, it might be Google Dot com, for example.
It might be one hundred sixty two point eight five eight two here and one hundred thirty two, for example.
So we talked in this.
You have to remember all of these IP addresses without is, uh, logically of the alphabet.
The numbers ordinance converts your domain name to IP address.
So and.
One of the most useful commands for the aspiring hacker is a thick.
Which offers a way to gather DNS information about the target domain.
So the sturdiness information can be a key piece of eerie reconnaissance to obtain before attacking.
So this information called include the IP address of the targets, name servers or the server that translates
to Target's name to an IP address, so the target's email server and potential and its subdomains and
IP addresses.
For instance, let's open our terminal here and enter the big league.
For example, Google Dot Com, you know, as you can see here and we got information from Google here,
as you can see here.
So.
Here and also, as you can see here, we have additional section here.
Degree was the IP address here.
Um, IP address of the DNS server for surfing and Google dot com.
So you can also use that the command to get information on email servers connected to a domain by adding
an X option.
So Amex makes the net short for mail exchange server.
As you can see here, we get so much information about that and for section here.
This is the Google's IP addresses, for example.
Let's get a mix here, right?
A mix here, and we will get, uh, these information here.
So what is this?
This is the information is critical for attacks on and on e-mail systems.
So, for example, info on the Google dot com email servers is shown in the authority sections here.
As you can see here.
Uh, so the most common Linux in a server is the, uh, purple, the internet's named domain b b in
the.
So in some cases, Linux users will refer DNS as B and D, but don't get, uh, B converts or the innocent
B on the be able to map individual domain names to IP addresses.
Uh, we can change our DNS um, server as well, though in some cases you may want to use another adding
a server.
So to do so, you will edit the plain text file names.
Uh, here.
Uh, cut it c uh, restore that Conficker.
Conficker, as you can see here, this is out.
Uh, this is just a small file.
As you can see here we read, uh, it with can't month cut program, so let's open it with leave at
the path.
Actually, it's not mousepad right, must, but it is here so that can here.
So here you will see, and as you can see here, there is a four.
So this is the read, as you can see here for for writing we we have to use sudo command into your college
password.
And as you can see here, this is the variety bill now.
So because of in which our current user, we cannot edit system files, but I used pseudo here.
So now when from the uh, resolv.conf configuration file, the ATC directory directory in my specified
graphical to text editor is, um, musketeer.
So as you can see on Line three here, uh, my name server is set to, uh, a local DNS server, um
uh, one hundred ninety two point one hundred eight, uh, six to eight point fifty eight point two.
And.
And that works fine.
But this, as you can see here, we can use we can use our tool means, for example, if I want to go
to Facebook.
Facebook dot com.
It works, uh, here.
Or if I want to go to Wikipedia here, uh, it works here too, as you can see here.
But if I want to change my DNS server, uh, we we can either replace it with this inside this file
here.
So Google's public DNS server is 8.8.8.8, so I will add the this DNS here.
But first, I want to show you here, uh, Google actually Dr. here.
And go, and this year, I will add Google DNS to my.
Uh, file here.
Google the and as.
Here, and I want to show you what is building this.
As you can see here.
8.8.8.8 here.
As you can see, this is a global city and as, uh, so we we can use Cloudflare seeing this as well
here.
But in this case, I will use the Wall DNS, as you can see here, there's so much being said or see
it.
Quote for DNS is one point one point one point one.
But Google is eight point eight point eight point eight.
So let's change.
Uh, these two 8.8.8.8 here.
And uh, I will add this line to here and.
Just save the file.
So how you can also achieve the same result in exclusively from the common line by entering air.
And call here, name, sir.
8.8.8.8.
And.
Show your cell phone.
Yeah.
Uh, it's uh, we will use pseudo rights because we cannot override.
And if I see her so I want.
Uh, let's check our minds, but as you can see here, we changed it.
So.
If you open them.
It is a resolve configuration file now you shall see that it points DNS requests to Google DNS server
rather than your local DNS server to resolve.
Your system will now go out to the Google public DNS server to resolve domain names to IP addresses.
This can mean domain names take a little longer to resolve problems in milliseconds and therefore to
maintain speed, but to keep the option of using the public server.
You might want to retrain the local DNS server in the install configuration file and follow it with
them.
Public DNS server the operating system and queries each DNS server list and listed in order to order
it appears in its resolve and configuration file, so the system will only refer to the public DNS server
if the domain name can't form in the local DNS server.