And Lou everybody when it comes to my advanced ethical hacking networking penetration testing goes
in this video we are going to talk about the security of the network.
So I'm to be more precise the security of the D H C.P. distribution IP addresses because sometimes let's
say that we have this network.
So we are he as the administrator or by configuring or a welder.
And and this is the server which provide the IP address for any kind of devices.
So let's say that an attacker wants to join the network to intercept the net worth to intercept the
network with his own server so that all devices get an IP address from his server so that he can get
control of all of our network.
So what he can do he can just try.
Okay let's see.
OK let's first.
So this project is something new so that we don't indeed save us well uh Dong
new attack over let's all get right.
So let's say the attacker says to himself.
Okay.
So he gets away so that he can join all he can connect to network.
So he brings his server right here.
So it's it's it's trying to find the server okay.
So he wins the server right here and then equal next to a welder.
So if see unit clinics or Walter so post this might work.
So let's change the name.
Let's check the stop feeling
version is server 1.
Let's see.
This is the ticker symbol.
Again right.
So let's say now when you are going to click on this computer it has a particular IP address which was
getting form which was getting Form D several super easy.
So what you can do though if if the attacker if if we had if we have this network as opening network
that is not source it's not secure at all because it does it prevent any kind of external devices to
enter or switch system.
Therefore when we won or when when we open a device or it might get an automatic IP address from us
or either from the attacker there or for the chance by by getting an IP address it will be net be depend
on us it will be like Windows.
So it will get any introduced either from us or from the attacker.
So let's let's configure this server of the attackers so that we can show you how it works.
So we click here and then we click on this top kill configuration.
So let's make this specific let's say 150 1 1 0 let's say 1.
So OK this is the IP address which the which is set for the server of the app of the attacker.
So now we can try to send a whinge or give the A C being let's say start IP address 1 1 0 let's say
1 1 0 case with the wind.
Is this one as we have set up the whinge for or 44 server on 5 5 1 2.
So we take.
But before can you say it on of course because we want to we want the server of the attacker might generate
a desire to speak IP address for all the network.
So we could save.
Okay.
So now let's go back and check it again.
All right.
Within these okay.
No.
Perfect.
Now let's check this one so let's just really fight this.
We had I feel good.
Oh OK.
Therefore let's try now to to open a computer or at all or a laptop and then go to configuration.
Put it on static and put it on DCP again to see how it will be.
So we check this one
DCP is successful and then it was before from this server.
Now it gets it from this server and it's very dangerous because the attacker might be very evil intention
and die.
And then he can try to get control of what he faces.
So let's check and order one.
And so if you if you just think it again probably it will take the first ip address again and again
it will just pick any one of them as window because now he had to.
He has two providers of server or of server which is one in the each server.
So it's sticky.
Again you see it takes it so let's put it back again again so we can try again if we take them as Windows
or we can just try to click here and go back again put it here again you.
So this is how it works.
OK.
So now what we want to do we want to secure all on it.
So by doing so we will stop any kind of intrusions from here.
I mean deport.
So anything that we try to into or switch will not be able to connect to do so we are going to use it
will go in and install it in India Cisco packets which called Snoop.
So we will not deport by snooping deport.
We will block despite these port disputes or any kind of a device we shall going through or switch to
go to all devices will be blocked.
Let's do so.
We just click on switch and then we go.
So that we made the configuration OK with cinder switch.
Now what we can do we can try this one corner in a ball game.
So we have it to anybody it anymore.
All right.
Again we type switch oil into a given month.
Now let's let's briefly expense one thing.
So before you so game OK well now do explore.
Let's check this again one more time to see that B you see 1 5 0 and then this IP is let's check it
1 9 2.
So do you expect this IP will be communicating with this.
Of course not.
If we want you can just try it by going through and simulation.
So just go here first and we can hear this message.
Would Hear put it here.
So with it here.
Excellent.
Now we're going to try to win it.
It's it's in progress
so let's see
you see fit.
Of course of course it must be failed because this one is getting an IP address from the server from
the attacker.
And this one still from this server.
I'm getting Minister metro because we need to configure it yet.
This this computer.
Let's let's check for example.
Let's check this.
If we click here and then click here again for the message.
We'll be communicating one less the IP address of this computer it gets changed so let's make it.
Let's try to do it first.
No go here so let's wait let's wait a moment the closest first to.
OK.
So go back again to
k you see to the IP address it's 16.
Go into my address.
Now it's eight.
Okay.
So therefore if we want to communicate them now yes it would it would work.
So let's try it here.
Here
and then you can go to simulation
software you see successful because now it's working on this computer to this computer.
It's working.
So we have just to check this now or task was about to do snot beat.
So Katie you now can just try to type IP address like this first as we get to change the configuration
mode
now let's boyfriend open now let's briefly explain how this system works.
OK.
So from this kind of ideas to be so we can each just see pistol vision or we can just call it denial
of service attack.
So when we anybody is snooping on the switch.
So the default attitude of the DCP snooping becomes to know what does that mean.
It means that it does it just a need.
Any devices which any devices to begin with each server for example any devices which enter D.
Are we disputable because we are going to stop a live report from intrusion or switch.
Yeah.
So.
So it stop any DSP server type message or for an acknowledgement.
Yeah.
And it lowers Klein text message discovery and we guessed that therefore after enabling the to be snooping
on ports we can only chose.
So even the part of the administrator.
So form this server will become untrusted because we don't set it as a specific address or specific
suits entries which can or which has access to internet or system.
So what we can do if any port of switch is a heavy new ideas to be server connected to eat that port
must be the ECP stooping chopstick port to acknowledge or switch to the specific to the administrator
server.
So we have to put the same report as just ID even port security protect or network from the ISP service
and starvation attack.
We may also said oh wait.
I mean they limit our untrusted port of switch to products and the to be starfish and attack not doing
it but it's this on the switch.
We have to enter the global configuration mode when we when we talk about the global configuration what
it's like.
So we just click here and we go to common line.
So we just always exist.
Okay.
So we just type config and we know.
So we are there.
So this is the global configuration model.
All right.
So as default Delenn of all network is said he is sitting on one on one.
So to throw into the interface.
So for example let's say for fast internet connection or fast as he was you will if you want to see
what is this.
You have a judge to hover over your mouse over each port so that you can get down.
So we override you see if it is you if if it is you will 8 your over over it.
OK.
You see.
So we do the same for us.
Check this.
Put it here.
All right.
So that's how you can make it.
OK.
So and then you can also check the binding by typing to IP the interest to be stopping binding.
All right.
So now let's get into the protocol ports as a whole.
We are going to endure the confusion what as we have been already.
So what we are going to take therefore is a choice a p h c and then we petition y everything.
If we don't know what type the quota Trimble condition.
So what we need now we need to snooping.
So we tied snooping and backstab.
And again if we want to in that condition Mark you see we see that is information verified violin and
so on.
What we need we need revealing scenes or default villain is setting who is setting on is set up on one
so we can just type realign and TAB Len in place or type 1 and then be present.
So far so good.
Now we have blocked all this port all of these port get get some bugs if you want to make sure if it's
true we can just go here and try to go back to any computer.
Let's say this one device and we're going to stop which is now reported back on static so that we can
get an IP address from any server for either from the attacker or from us and therefore it will not
get any IP address because we have blocked this port from the switch.
All right so we click here.
Again the process should be wait a little bit longer and we will not get any IP address from 1 9 2 0
1 5 0.
So let's check it.
So let's wait and then it should be fade.
Let's wait a moment just to see if we can drag this
guest an IP address.
Exactly.
You see the HCV fed it gets an APB it paid IP address which is Fred is being used.
Okay.
So that's how it works because when we set up when we set up or was snooping so we that means we broke
on the platform into doing the switches week.
OK.
So again just try to go back here and try this on yeah.
Doing so
weakest in IP addresses you see again failed.
So again failed.
So that's how it works
now.
It's just a matter too I know some port to be trusted.
So that's why we now type need C.P. IP and then we typed Snoop and just therefore we chose that particular
port.
All right okay.
Let me show you right now.
Let's.
Let's assume that we don't want to prevent this kind of access.
We want to have this access by doing so we will make us as being a trusted external source.
So to do so we are going to go to the terminal command that is terminal command.
Now we should try to check on which interfaces which is going into the water to the switch.
I mean so by doing so we just over a mouse disease interface f it all and eight.
This one is 0 5.
Okay and 0 6.
Now what we can do ORS is 0 5.
Now we have to enter that differs.
They do need.
We will give us access.
So we type interface.
And if it's a 0 5 percent.
Okay.
And now we are there.
Now we will try to snap us so that we can give us access by not limited but B as being trusted.
So we type IP address C and smoke was this.
Now we get the option of limit DHS CPS snooping limit choice the ACP slipping chose conflict.
We want us to be trusted.
Now we are going to take choice and we can put quotation mark again.
So that means we have c o.
So the comment is OK.
So again just put in derm.
So now we have access.
Now we have access to to this switch all the order but does it have access.
So we can try it now.
So let's go here again quick here.
So now each should it get an IP from the server attacker from the attacker of server it should have
get access only from these server from us.
So you check here and again go back here excelling you see perfect.
So just the this one it's one perfect.
Successful again.
Let's try because before it's Jenny waits sometimes days and sometimes days.
Now we blog this all of over all of them all external sources except this one.
So that's why when we are we fetching it.
It should be only from this server.
So on time
perfect.
All right so let's check this one now.
It is six
again.
Perfect.
So now guys this is a very very well known way how you can secure your network because this is the way
that we choose to make to give access as being trusted means that do the switch say hey I believe this
guy this guy I know him.
So I can open my door so that it endures and manipulate my devices.
So it's not a problem for him because he's my friend but all the older ones you know if that's if an
attacker twice tries to do get access to a system enjoy to insert a server it is DCP server so that
he can control the devices.
This switch will say hey my friend I'm so sorry for your gain I'm so sorry for you because I have only
one friend and that when is server zero I know him some time it goes on and I trust him but I don't
trust you.
Okay.
So please stop.
You know so therefore your network becomes more secure than how it was before.
So that's how we can figure this lopping off of the S.P. server.
So by doing so we prevent all the external sources from entering by and by giving access to only one
trusted bot.
So now we can check how many new vaccines are made it would cost to network.
So by wanting to do so by wanting to do so we can just executive what happens tomorrow.
So no no switch okay.
So let's try to make this one the
case successful take on ICS into this and for the older ones
safe and successful.
You do this in
excellent X eggs we do this in
case which is one of this is six.
Okay.
And then this one was what OK.
All right.
So Kiki go here again.
Perfect.
So now all these devices are warning or it's a default with a window IP I just get getting from the
server.
So we can back.
And then we are going to type.
Should I leave the HCV snooping and binding now stop the new presenter here we are guys.
So this is the Mac address which we get from this particular I'm watching this particular machine belongs
to these countries.
You see it's so funny.
And it's it's really working guys you know so you can get much more information about what you have
and some stuff like that.
It is on veal and one but all of them is unreal and one and then the type is DHS CPS snooping and the
IP address is these one.
You know there's this one.
This one is the IP address and an address for each of them right here in the left side.
So now what we can do we can try to get a notification of what we can do.
We can try to get a notification when when a change is made on our network.
So to do so we have to use the the command debug so that we can get the information in.
Oh to me now why the change or a modification why why if someone is turning this system that work OK
now let's prepare yourself for any kind of event which is made on a network so to do so we are going
to tie you see we may be debug.
I'd be subpoenaed as these and so being of course start again and event.
So we check for the event.
OK.
Zero so we can endure it now.
All right.
So now we are waiting for any kind of request which is made on our network.
So.
All right let's.
All right.
So let's go.
Here you go.
Here some kind of
and
it's here.
So you can just click again here on any computer on any device.
Sure.
Yeah.
We care.
Okay.
So now let's go back again to static soil and then let's make a request from the Chesapeake wait you
see automatically we get it to hey you guys.
You see switch.
It was your 13 is who you were nine.
Andy it's obviously adding binding an on board as you will one.
So let's check this one so we can just do that and what it's 0 1.
This is it 0 1.
So let's check this tape.
Let's say this one or a game that's here with a laptop and let's me then guess then the request again
excellent port 0 2 fast internet.
So it was this one laptop.
It's over over a mouse.
Yeah.
So let's check day decode one enough to give us once again
you see excellent excellent days and the last one.
So if you want you can do it for all of your devices it's not a program but we just want to show you
some of them.
So yeah.
And reading.
Yeah.
So that's how old guys.
You check a modification which is made or any request which is made on your server by your devices.
So you'll get the information and then the time you know you get the information the time is setting
up very excellent.
So yeah.
OK
that's all for these video guys.
We hopefully think that this video was informative for all.
And we are looking forward to seeing you in the next video.
Thank you.