Hi, everyone, in this lecture, we are going to talk about DCPI and IP, so to become a proficient
hacker forensic investigator or simply be a good network engineer, you should understand the structure
and anatomy of these protocols.
From my experience, many professionals in these fields do not understand the basics of PXP IP, which
means that you will definitely have an advantage over them if you do understand TCP IP.
So to create a new hacking to or investigate a network attack.
Understanding these protocols and their fields is very essential.
Otherwise you will be simply wasting your time.
So guys, let's see what is a protocol.
So protocol simply defines our way of communication with all its rules.
So these rules are usually defined as a request for comments.
So there are many, many protocols in use on the Internet.
So these include DCP, IP, UDP, FPP, S2P, SMP and many more.
So each has its own set of rules that must be combined with in order to communicate effectively.
So probably the two most important protocols for use over the Internet are IP and PXP.
So now let's take a look at each one of these.
So first of all, we are going to talk about Internet protocol.
So before doing it, let me select this.
OK, so Internet or IP standard protocol and IP.
So IP is the protocol that is used to define the source and destination IP address of a packet as it
traverses the Internet.
So it is often used in conjunction with other protocols such as PXP, hence the often used conjunction
TCP IP.
So now let's take a look at an IP packet header and see what information it contains that can be useful
to aspiring hacker or forensic investigators.
As you can see that this is the data packet.
So guys, if you talk about the raw one.
If you talk about this, it contains was so wasn't the defines the version of i.p either it will be
full of Visigoth then we are having a Etchells, which is Healthland.
So Dissembler defines the Hadland, then we are having type of service, which is called B OS.
So this defines the type of service of this packet.
So this includes minimum, minimize delay, minimize throughput, minimize the reliability and minimize.
We can see more cost.
OK, so then we're having total lenth.
So what it is so totally simply defines the total length of IP data gumps, including the data or the.
OK, so it's maximum value is like three six five fifty five.
OK then let's talk about rule number two which we have here.
So first thing that we have is ID.
So this feel uniquely identifies each packet.
It can be critical in resembling fragmented packets.
Then we are having IP flagged.
So this field defines whether a packet is fragmented or not, which is called B, OK, so the manipulation
of the field can be used to invade ideas and firebase.
So, guys.
Next, we are having a fragment opposite.
So this field is used when packets are fragmented and defines where the packets should be reassembled
from the beginning of the IP header.
OK, is this clear?
Now, let's talk about rule number third.
So here we are having TPL, which is called As Time to Live.
So this defines how many homes across the Internet before the packet expires.
So it varies by operating system, making it useful to identify the voice of the sender, then we are
having protocol.
So this will defines what protocol is being used with IP.
So most often it will be six or PXP or one or ICMP 17 for UDP, among others.
Then we having had a checksum, so what it is, so this is an error checking feel, it calculates the
checksum to determine the integrity of the data in the header.
So now let's talk about rule number four and rule number five.
So here we are having source and destination, so these rules of the Apiata are probably the most important
part of the header as it contains the source and destination IP address.
OK, then we are having rule number six, which is very important.
And the last here.
OK, rule number six.
So it contains options.
So this feels is very balanced and it uses it option.
And then we are having padding also here.
So what bearing is supporting this will is used to fill out, if necessary, the remaining bits and
bytes of the header.
So this is all about Internet protocol.
Now let's talk about transmission control protocol, which is TCP.
So we are having this DCP header scenario to start with the rule number one.
So this is the Rodemeyer one.
OK, OK, so the number one, it is containing source code and destination board.
So probably most importantly, these are the source code and in destination, both these fields, it
determines what board the communication came from and where it is going.
Then we have having rule number.
Second, which is sequence number, so the citizen number is generated by the source, Mrs. BCB stock,
and is used to make certain that packages are arranged in the proper sequence when they arrive.
So it is also important in defeating man in the attack.
Then let's talk about rule number three, which is acknowledgement, no.
So this is an ego of the sequence numbers sent by the receiving system.
It is basically says that I received the package with the sequence.
So in this way, the sender knows that the packet arrived at the sender does not received an acknowledgement?
No.
Back in the fixed amount of time, it will be releasing the packet to make certain receivers get the
packet.
In this way, TCBY is reliable.
Then we are having rule number four, which is containing so many things.
So no food has some critical information.
So now let's give the data opposite and result fields and that takes us to a right near the middle of
the photo.
So these are the infamous flag of the three way handshake and and maybe can also.
So the first debate, which as you can see, a W, R and E, C, E, so Arben are beyond the scope of
this particular lesson because they are too complicated.
The next six bits on you are G.
AC k p s h oreste x, y and and affianced, let's see each of each one of them in my detail.
So what is sinc sync is nothing, but it is the opening of a new connection.
What is sin?
We have talked about this.
Then what is Finn Finn?
It is the normal and soft closing of the connection.
Then we are having X.
So the acknowledgement of a packet of all packets after three Hadzic should have disappeared, said
then we're having Oreste, which is here.
So the hard close, all the connection and usually used to communicate that the packet has arrived at
the wrong port or IP, then we're having a which is you are cheap.
So this flag indicates that the following data is urgent.
Then we are having a down last but not least push, which is BSF.
So push the data, it will push the data past the buffer to the application.
So this is how it all works.
We have talked about some padding options, Origin Point and IP Protocol S..
So guys, this is all about CPPIB, how it works.
What are the protocols and what are the header of these protocols?
So this is all for this lecture.