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In this lecture, you will manipulate the domain name system the and.

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Hackers can find a treasure trove of information on a target in its domain name system DNS, so DNS

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is a critical component of the internet.

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So and although it's designed to translate domain names to IP addresses so A. can use it to garner information

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on the target.

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And Dennis is a service that translates a domain name like, for example.

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Let's open their browser, and they will, for example, Google that come to appropriate IP address.

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So I will show you an installation of the end this year will come here.

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Actually, our internet is disconnected because I log out our.

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Network adapter here, and I will fix it now here.

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Let's see if I see a doctor go.

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Uh, we will.

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Conduct a core here, and I will search here the in this, uh.

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And I want to show you an illustration here for better understanding.

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Uh, so actually.

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In this.

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War.

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Here, as you can see here, the uh, let me open here.

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So, um, this is them our possible attacks here.

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So first, I want to talk about, uh uh, is, uh, Google here, for example.

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Um, it DNS is a service that translates a domain name, uh, for example, like, uh, Google dot com

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to IP address.

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So the way your system knows how to get to do it, so without Dennis, we will all have to remember

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thousands of IP addresses like that.

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For example, in Google, it might be Google Dot com, for example.

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It might be one hundred sixty two point eight five eight two here and one hundred thirty two, for example.

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So we talked in this.

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You have to remember all of these IP addresses without is, uh, logically of the alphabet.

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The numbers ordinance converts your domain name to IP address.

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So and.

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One of the most useful commands for the aspiring hacker is a thick.

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Which offers a way to gather DNS information about the target domain.

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So the sturdiness information can be a key piece of eerie reconnaissance to obtain before attacking.

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So this information called include the IP address of the targets, name servers or the server that translates

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to Target's name to an IP address, so the target's email server and potential and its subdomains and

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IP addresses.

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For instance, let's open our terminal here and enter the big league.

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For example, Google Dot Com, you know, as you can see here and we got information from Google here,

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as you can see here.

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So.

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Here and also, as you can see here, we have additional section here.

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Degree was the IP address here.

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Um, IP address of the DNS server for surfing and Google dot com.

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So you can also use that the command to get information on email servers connected to a domain by adding

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an X option.

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So Amex makes the net short for mail exchange server.

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As you can see here, we get so much information about that and for section here.

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This is the Google's IP addresses, for example.

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Let's get a mix here, right?

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A mix here, and we will get, uh, these information here.

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So what is this?

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This is the information is critical for attacks on and on e-mail systems.

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So, for example, info on the Google dot com email servers is shown in the authority sections here.

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As you can see here.

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Uh, so the most common Linux in a server is the, uh, purple, the internet's named domain b b in

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the.

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So in some cases, Linux users will refer DNS as B and D, but don't get, uh, B converts or the innocent

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B on the be able to map individual domain names to IP addresses.

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Uh, we can change our DNS um, server as well, though in some cases you may want to use another adding

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a server.

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So to do so, you will edit the plain text file names.

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Uh, here.

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Uh, cut it c uh, restore that Conficker.

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Conficker, as you can see here, this is out.

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Uh, this is just a small file.

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As you can see here we read, uh, it with can't month cut program, so let's open it with leave at

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the path.

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Actually, it's not mousepad right, must, but it is here so that can here.

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So here you will see, and as you can see here, there is a four.

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So this is the read, as you can see here for for writing we we have to use sudo command into your college

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password.

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And as you can see here, this is the variety bill now.

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So because of in which our current user, we cannot edit system files, but I used pseudo here.

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So now when from the uh, resolv.conf configuration file, the ATC directory directory in my specified

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graphical to text editor is, um, musketeer.

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So as you can see on Line three here, uh, my name server is set to, uh, a local DNS server, um

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uh, one hundred ninety two point one hundred eight, uh, six to eight point fifty eight point two.

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And.

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And that works fine.

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But this, as you can see here, we can use we can use our tool means, for example, if I want to go

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to Facebook.

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Facebook dot com.

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It works, uh, here.

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Or if I want to go to Wikipedia here, uh, it works here too, as you can see here.

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But if I want to change my DNS server, uh, we we can either replace it with this inside this file

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here.

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So Google's public DNS server is 8.8.8.8, so I will add the this DNS here.

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But first, I want to show you here, uh, Google actually Dr. here.

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And go, and this year, I will add Google DNS to my.

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Uh, file here.

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Google the and as.

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Here, and I want to show you what is building this.

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As you can see here.

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8.8.8.8 here.

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As you can see, this is a global city and as, uh, so we we can use Cloudflare seeing this as well

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here.

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But in this case, I will use the Wall DNS, as you can see here, there's so much being said or see

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it.

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Quote for DNS is one point one point one point one.

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But Google is eight point eight point eight point eight.

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So let's change.

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Uh, these two 8.8.8.8 here.

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And uh, I will add this line to here and.

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Just save the file.

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So how you can also achieve the same result in exclusively from the common line by entering air.

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And call here, name, sir.

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8.8.8.8.

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And.

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Show your cell phone.

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Yeah.

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Uh, it's uh, we will use pseudo rights because we cannot override.

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And if I see her so I want.

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Uh, let's check our minds, but as you can see here, we changed it.

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So.

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If you open them.

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It is a resolve configuration file now you shall see that it points DNS requests to Google DNS server

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rather than your local DNS server to resolve.

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Your system will now go out to the Google public DNS server to resolve domain names to IP addresses.

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This can mean domain names take a little longer to resolve problems in milliseconds and therefore to

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maintain speed, but to keep the option of using the public server.

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You might want to retrain the local DNS server in the install configuration file and follow it with

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them.

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Public DNS server the operating system and queries each DNS server list and listed in order to order

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it appears in its resolve and configuration file, so the system will only refer to the public DNS server

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if the domain name can't form in the local DNS server.