Original subtitles

I'm sorry.

Where are we?

What's going on?

Oh yeah.

Hey, look at this.

We're in the next lesson.

Hi, guys.

So hey, we're going to now learn about TCP IP.

Now it sounds kind of weird, but actually, it's quite simple.

I'll break it down for you.

TCP IP.

It's a communication method on the internet that was created by combining TCP or transmission control

protocol and IP, the internet protocol, and they put them all together and called them TCP IP protocol.

So it's thanks to these methods.

All devices connected to the internet can communicate with each other.

At the same time, I mean, that's kind of mind blowing if you really stop to think.

Anyway, computers connected to a network communicate with each other via this TCP IP protocol, and

they transmit and receive data.

That's it, right?

So in short, TCP IP is a set of communication protocols that sets the rules for data communication

between computers.

So communication between computers is carried out over different protocol families or types.

According to the purpose of use, these protocols are separated from each other.

In fact, I'll give you some examples.

FTP is actually short for file transfer protocol, and it is what it does a file transfer protocol.

While S.M., T.P. or Simple Mail Transfer Protocol is used for guess what?

Transmitting email.

The S.H. Protocol is used for management purposes by creating a secure tunnel on Linux systems.

So just put that on the back burner.

But I do want to tell you about TCP IP as a protocol family to understand it just a little bit better

will first need to learn what TCP and IP protocols actually are and do so.

What is TCP transmission control protocol?

It's a protocol that allows communication between computers to be carried out in small packets and without

loss.

So in fact, the most important feature of the TCP or transmission control protocol is to authenticate

and ensure the integrity of the data when sending a receiving data to the other party.

All right.

So.

You can actually think of it as party favors and party snacks getting delivered.

Oh boy.

Right?

This TCP IP protocol was written to prevent losses in advance, computer networks, data transmission

of protocols that we frequently use in daily life.

You might even be familiar with some of them.

HTTP, https, POP3 or POP3 each SMTP telnet FTP.

These are all done via TCP.

Starts sound like an alphabet soup after a while, huh?

But P stands for protocol.

So how does this TCP or transmission protocol actually work?

Well, the working logic of the TCP can be examined under three headings, I think in the first.

A connection request is sent to the destination.

And the second stage, the connection is confirmed and then the data transfer begins in the third stage.

The connection is terminated by sending it to the parties where the data transfer is completed.

So the realization of these three things or three stages, this is all defined together as this state

process.

So how do you establish a TCP connection?

Well, in TCP, some intermediate situations also occur for the realization of these three main stages.

These intermediate situations are listed like this.

Listen.

Makes sense.

But the lesson is this state in which a TCP connection request is expected by the server.

It's called listening mode.

Sin sent so after a TCP connection request is sent to the other party.

It's called the situation where the connection requests from the other party is expected to be answered.

Sin received.

This is called the waiting state after the server responds to the connection request made with the sin

flag by sending the sinek flag.

OK, so the server's response is sending back a sinek flag.

All right, don't worry about it.

Stay with me here.

Established this is a situation in which the incoming data transfer is made after the connection is

established.

Now, Finn, wait one.

Well, this is the wait state on the server and the client.

So I.

Finn, wait, too, this is the state where the request to terminate the TCP connection from the other

party is expected.

Close wait.

All right, so this is the state in which a connection closer request is expected by the server and

the client.

And closing the state of waiting for the end of the connection after an act flag is sent to the other

party to end the connection.

Last week.

So this is this state where the attack is expected on the server and client side.

Time, wait.

Well, that's a standby state.

Closed.

And this state is called when the TCP connection is completely dead.

So while establishing a TCP connection, that is when two computers want to establish a connection with

each other over this TCP protocol, the processes begin to take place in the following order.

One, I'd say Computer X sends a TCP syn message to computer, y to computer y sends it TCP Syn Act

message that it has received the request of Computer X.

Three Computer X sends TCP Ach message to Computer Y.

For Computer Y receives an ACH TCP connection is established message back to Computer X.

Right.

So it's as a result of this method that we call a three way handshake.

TCP connections are opened and then the process is provided successfully and safely.

So there is a whole incredible method to all of this, what would appear to be madness, right?

So while making a TCP connection.

A process called three way handshake is performed as as we just went over right, so this sequence of

operations goes like this one, the client sends a sin packet.

To the server.

To the server responds to this packet with Sinek data packets.

Three, in the last stage, the client computer sends an ACC message to the server and the first communication

is started.

If the client transmits a connection request to a non listening, that means a non open port of the

opposite server during this process, which, by the way, must be in lesson mode.

Well, the RC t Ach response packet is sent from the server instead of the above mentioned sinek packet

response from the server.

So at this point, the server will have refuse a connection and the connection will not be established.

The.

RCD packet is defined as reset and.

It's also used to disconnect an open connection.

All right, so moving right along here, we've got this big question, so what actually is IP?

I mentioned that IP is the abbreviation right for Internet protocol.

But this is the order that's used in network addressing, which is the most important point in the communication

of computers with each other because IP or internet protocol is defined as a protocol that provides

routing of packets between two computers, right?

So here's the key word routing of packets.

Another way to define IP is a protocol that provides the routing of packets between two computers.

So we define it as the routing protocol, right?

IP determines the routing rules required for data.

Now, the nature of the data is not important in IP, and this protocol only determines the destination

address regardless of the data content.

All right, so now that's all clear as mud.

Let's move along to how does IP this internet protocol actually work?

Well, in IP lighting, the path to be followed by the TCP data packet is determined.

So while doing this, it adds its own segment header to the data packet coming from the TCP layer.

And in this case, a data Graham is sent.

So while IP or internet protocol for words data to the other party, it does not verify whether the

receiver will accept or reject this data.

Right.

So error checking is actually the job of an upper layer, and this IP is known as a self-executing protocol.

All right.

So just kind of sticks to itself.

So what are the TCP IP layers then?

So TCP and IP combine to form this TCP IP protocol family, and in this way, more than one communication

method can be used between computers.

The TCP IP layers used during this communication are right here as follows.

This is the TCP IP reference model.

Layer four, application layer three, transport, layer two network, layer one network interface.

All right, so we've got the application layer, right, so within the application layer, communication

between processes and applications on different servers is provided.

Now it's during this communication protocol, such as HTTP https as S.H., as SMTP, Telnet and FTP

are used.

Then we have the transport layer, so the transport layer is the one that provides the data flow from

one point to another.

TCP and UDP are the protocols that are used on this layer.

And then we come to the network layer.

So the network layer is used to provide the necessary transmission of data from a source to a target

computer between router devices and networks connected to each other.

So any information used during this data transfer is transferred with the network layer.

But that's not to be confused with a network interface layer, so it's in the network interface layer

that the connection interface between the endpoint and the network is used.

So computer languages remember consists of zeros and ones, and for communication in this layer, data

packets are transported by converting zeros and ones.

All right.

So that's it for all of this.

It's called the alphabet soup and I guess, huh?

But in any event, now you know about IP and TCP and its respective layers.

All right.

So thanks a lot for listening and hanging in to the end.

But we've got more in store and that's coming up in the next video.

I'll see you then.