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Let us start with the news section scanning and enumeration in this lecture, we are going to learn

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an overview of network scanning.

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So what is scanning?

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Scanning is a set of procedures for identifying a Laveaux port services, discussing operating systems,

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architecture of target system, identifying vulnerabilities and threats in the given network.

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Network scanning is used to create a profile of the target organization.

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Scanning refers to collecting more information using complex and aggressive reconnaissance techniques.

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So water object use of network scanning to discover lifeforce and Computer's IP address.

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Open borders of the target victim to discover services that are running on the host computer, to discover

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the operating system and system architecture of the target.

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To discover and deal with the vulnerabilities in life of every organization has a network.

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This network could be an internal network which consists of all the systems connected to each other.

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Or it can be a network that is connected to the Internet.

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In either case, to hack the network, you will have to find a vulnerable point in the network that

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can be exploited.

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Network scanning is used to find such vulnerable points.

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So how networks can be different from information gathering?

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Well, think of it as like this.

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You are an Army officer and you and your team are planning to attack a terrorist lair.

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You fond of the location of the lair and details about the surroundings and also the ways to send them

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to the letter.

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You can consider all the information you have gathered using the information gathering phase.

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Now you have to find a point through which you can enter the terrorist organization and attack the enemy.

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This is network scanning in simple terms.

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Information gathering is used to gather information and understand your target.

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And network scanning is a method used to find possible vulnerable points in the network through which

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you can hack the network.

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Depending on what kind of information the scan identifies, it was scanning can be classified reports

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or scanning and vulnerability scanning for learning the network scanning files you need to learn.

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DCB Connection establishment also called as three way handshake.

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BCB three way handshake is a process which is used in a discipline at work to make a connection between

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the server and the client.

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It is a three step process that requires both the client answerable to exchange synchronization and

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acknowledgement package before the real data communication process starts.

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A three way handshake process is designed in such a way that both and help you to initiate, negotiate

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and separate TCP socket connections the same time.

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It allows you to transfer multiple DCB socket connections in both directions at the same time.

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But DCB traffic begins in a three way handshake.

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In this distribution process, a client needs to initiate the conversation by requesting a communication

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session with the server.

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So how is the process of prevention in the first step?

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The client establishes a connection with the server.

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It sends a signal to the scene.

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There is the Synchronization Baggot and informs the server about the client that through the communication.

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We start with that.

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The client also sends the sequence number in the second step server response to the client with Senex

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in that synchronization and acknowledgement, acknowledgement helps you to signify the response of the

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segment that is received in the final step.

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The client acknowledges the response of the server and they both create a stable connection will begin

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the actual data transfer process.

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So let us have a summary of a DCP handshake and the first step.

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The client establishes a connection with the server.

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In the second step, the server responds to the client with Senex, Signal said set.

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And in the final step, the client acknowledges the response of the server.

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In the last lady, we saw the cockpit prevention process initiation.

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In this light, we will see DCB condition termination for terminating the condition Galion sense of

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Fynn segment.

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Finn stands for Finish the Server with it said to one gland enters the Fininvest state.

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One gland waits for an acknowledgement from the server after receiving the segment, server frees up

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its buffer's server since an acknowledgement to the client server enters the Clausewitz's state.

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After receiving the acknowledgement, client enters the freeway to state now the connection from client

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to server is terminated, that is when the connection is closed.

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Glan cannot send any data to the server since the server has released its buffer's, pure acknowledgments

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can be sent from the client server.

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The connection from the server to client is still open.

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There's one connection.

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It's still open.

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Server now can send both data and acknowledgments to the client.

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Now suppose server wants to close the connection with the client for terminating the connection between

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server and client.

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Server sends a phone signal to the client within a certain server waits for acknowledgement from the

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client, not a server wanted.

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It could have sent the Fehn segment along with the previous acknowledgement that it sent to the client.

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After receiving the final segment, client frees up its Bofors client sends the acknowledgement to the

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server, which is not mandatory, and then client and does the time red state.

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So all this time would state the time.

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Red state allows the client to present the final acknowledgement if it gets lost.

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The time spent by the client in time with state depends on the implementation, the typical values that

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thirty seconds, one minute and two minutes after the word, the connection gets formally closed.

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In the next lecture, we will see different scanning techniques.