Let us start with the news section scanning and enumeration in this lecture, we are going to learn
an overview of network scanning.
So what is scanning?
Scanning is a set of procedures for identifying a Laveaux port services, discussing operating systems,
architecture of target system, identifying vulnerabilities and threats in the given network.
Network scanning is used to create a profile of the target organization.
Scanning refers to collecting more information using complex and aggressive reconnaissance techniques.
So water object use of network scanning to discover lifeforce and Computer's IP address.
Open borders of the target victim to discover services that are running on the host computer, to discover
the operating system and system architecture of the target.
To discover and deal with the vulnerabilities in life of every organization has a network.
This network could be an internal network which consists of all the systems connected to each other.
Or it can be a network that is connected to the Internet.
In either case, to hack the network, you will have to find a vulnerable point in the network that
can be exploited.
Network scanning is used to find such vulnerable points.
So how networks can be different from information gathering?
Well, think of it as like this.
You are an Army officer and you and your team are planning to attack a terrorist lair.
You fond of the location of the lair and details about the surroundings and also the ways to send them
to the letter.
You can consider all the information you have gathered using the information gathering phase.
Now you have to find a point through which you can enter the terrorist organization and attack the enemy.
This is network scanning in simple terms.
Information gathering is used to gather information and understand your target.
And network scanning is a method used to find possible vulnerable points in the network through which
you can hack the network.
Depending on what kind of information the scan identifies, it was scanning can be classified reports
or scanning and vulnerability scanning for learning the network scanning files you need to learn.
DCB Connection establishment also called as three way handshake.
BCB three way handshake is a process which is used in a discipline at work to make a connection between
the server and the client.
It is a three step process that requires both the client answerable to exchange synchronization and
acknowledgement package before the real data communication process starts.
A three way handshake process is designed in such a way that both and help you to initiate, negotiate
and separate TCP socket connections the same time.
It allows you to transfer multiple DCB socket connections in both directions at the same time.
But DCB traffic begins in a three way handshake.
In this distribution process, a client needs to initiate the conversation by requesting a communication
session with the server.
So how is the process of prevention in the first step?
The client establishes a connection with the server.
It sends a signal to the scene.
There is the Synchronization Baggot and informs the server about the client that through the communication.
We start with that.
The client also sends the sequence number in the second step server response to the client with Senex
in that synchronization and acknowledgement, acknowledgement helps you to signify the response of the
segment that is received in the final step.
The client acknowledges the response of the server and they both create a stable connection will begin
the actual data transfer process.
So let us have a summary of a DCP handshake and the first step.
The client establishes a connection with the server.
In the second step, the server responds to the client with Senex, Signal said set.
And in the final step, the client acknowledges the response of the server.
In the last lady, we saw the cockpit prevention process initiation.
In this light, we will see DCB condition termination for terminating the condition Galion sense of
Fynn segment.
Finn stands for Finish the Server with it said to one gland enters the Fininvest state.
One gland waits for an acknowledgement from the server after receiving the segment, server frees up
its buffer's server since an acknowledgement to the client server enters the Clausewitz's state.
After receiving the acknowledgement, client enters the freeway to state now the connection from client
to server is terminated, that is when the connection is closed.
Glan cannot send any data to the server since the server has released its buffer's, pure acknowledgments
can be sent from the client server.
The connection from the server to client is still open.
There's one connection.
It's still open.
Server now can send both data and acknowledgments to the client.
Now suppose server wants to close the connection with the client for terminating the connection between
server and client.
Server sends a phone signal to the client within a certain server waits for acknowledgement from the
client, not a server wanted.
It could have sent the Fehn segment along with the previous acknowledgement that it sent to the client.
After receiving the final segment, client frees up its Bofors client sends the acknowledgement to the
server, which is not mandatory, and then client and does the time red state.
So all this time would state the time.
Red state allows the client to present the final acknowledgement if it gets lost.
The time spent by the client in time with state depends on the implementation, the typical values that
thirty seconds, one minute and two minutes after the word, the connection gets formally closed.
In the next lecture, we will see different scanning techniques.