Hey, guys. Welcome to another episode of the S S C P Exam Prep. I'm your host, Peter Simple in this is going to be the sixth domain Lesson two.
So far in the six domain, we've taken a look at the O. S. I and the TCP ikey models. We took a look at how it requires seven layers for a user to send information across the network to another user. And now, in this lesson,
we're gonna take a look at, I mean that working
specifically the Internet protocol and how it works to send data from one spot to another, let's get started.
In order to exchange information across the network, you need to send it through packets using Internet Protocol, otherwise known as I P.
I. P is responsible for sending packets from the source to destination who's now source and deaths. Each host
or computer is distinguished by an I P address. So an example of the 1 92.1 68.1 45.1 23
i p addresses is like a little address for each computer that tells the computer where to send the information. So I p addresses or divided up into a network number and a host number. Now the network number determines which network class it belongs to,
and the host number determines the actual computer inside that network class. So there are five different network classes A, B, C, D and E. And the range of the first ock tent tells us while which which class the I P address belongs to.
Now. Octet is the 1st 3 numbers in the
in the I. P. Address. So the 192 would be the first ock tent with 168 would be the second and someone.
So just by looking at the 1st 3 numbers of the I p address, you ca n't tell what what class it belongs to. And you can tell how many ock tents are required for the network number.
So in our example 1 90 to 1 68 1 45 1 23
we see that the 1 92 is associated with Class C, and it requires three AQ tats for the network number. So that means the 1 90 to 1 68 and 1 45 is our network number,
and then the 1 23 is simply the host number.
Now, with this class, see, the number of hosts in this particular network is 254.
classless inner domain rounding
allows flexibility to access Maur I p addresses. So when the first, the first thing started when the internet started way back when there were plenty off I p address. So everybody, whatever. They're not whatever network class they've got set up on, that was how many ikey addresses they had.
there are limitations to the number off I P addresses poor per network class. And I was that did not allow for a whole lot off flexibility.
As you can see, Class C only has 254 addresses. Well, suppose a company needed 300 addresses. Classy wouldn't help. So they would have to use Class B, which would be 65,534. Well,
they only needed 300.
They didn't need all this extra ones, but they had to get all this extra ones anyway in order to have 300 address
Now, this wasn't really a problem until the nineties, because nineties was when the Internet exploded and caused a shortage of unallocated I p address. There were just too many devices and not enough addresses, so to help the problem, cider was invented.
Cider does not require a new address be allocated based on the number of hosts in the network class. Instead, addresses are allocated in continuous blocks from pools of unused
sub nets. Some nets are a logical subdivision off a network just for really network and administrative purposes. Networks get divided into sub nets, so they are easily managed.
Some. That mask is used to define the part of the address that is used for the particular sub net. So what I mean by that?
Well, in our example, the 1 90 to 1 68 1 45 1 23 Usually at the end, there's a slash and then a number, and that number is known as the Southern that mask. So in our example, our numbers 24 to 24 is the sudden that mask
now. This means that out of 32 bytes, because that's the maximal number I could possibly be. 24 of them are being used, so it's 24 ones out of the 32 so you can write it like that
or to keep it simple, Jens the more commonly way of seeing it to 55 to 55 to 55 0
This means that the 1st 3 numbers in three first three octet it's rather need to be the same in order for two hosts to be on the same sub net. So and then our example. If we had ah, device with an I p address off
that would be on a different sub net than a device that was 10.1 dot to 0.26.
So I p v six This is the modernization of I P V four. Again, there are just too many devices and not enough addresses. So people are starting to move to IBT six, which has a much larger address field in the I P G Force 128 bits. It also offers improved security,
a more concise packet header
and a better quality of service
Border Gateway Protocol B g p. This exchange is routing information between Gateway hosts.
This causes the Internet to be a fully decentralized network. The protocol. This is the protocol used between the hosts
and the Internet. So when you are going from network to network writer, that's on the very edge of a network that needs to send the information to the router. And another network would use B g p in order to get the information there.
D, c, p and u D p ease our data connections through which port numbers are associate ID with service is now ports are managed by the Internet assigned Numbers Authority and are really just a little slots that different applications used to
plugging data to send from
one spot to another. Now there are 65,536 ports broken into three categories, well known,
which are reserved ports. These are for things such as ftp SMTP http There's registered ports which could be used for less popular things
or these arm or ports use for developers. And then there's dynamic ports, which make up the last group on anyone can really use these ports.
So this is how TCP works, All right, this is how a TCP connection gets set up.
The client wants to send something to the server, so he sends a sin request
the re server receives. It
sends back a sin request to synchronize and enact for acknowledging that they have received the client's original synchronous request
decline, then sends in AC and Acknowledge request and a sequence number and then start sending the data. This is how TCP is set up. It sets up a connection to provide error free handling.
This is the best difference between TCP and UDP.
DCP provides a connection, as we just looked at, has error handling and tracks packets to make sure all the packets get there.
Examples of things that use D c p R H T T p on SMTP
ew dp, on the other hand, is known as best effort. If if it gets to the destination, it gets to the destination. And if not, well,
It's completely connection list. Just spit that information as fast as they can and use it and does not have error handling as well. So if the packets get lost, then packets get lost.
An example of UDP would be voice over. I p
d h c P and I am C P D. A. C. P. This is dynamic host configuration protocol. This is a protocol that assigns I P addresses automatically to work stations, so I t members don't have to do it. Mainly, all you do is simply
connect to the WiFi or you look in it either in that court
on an I P address will be assigned.
This address is given for a period of time, and the lease is referred to as a T. T l or Time to live
once the t t l reaches zero. Then the next time you try to access the Internet or get Internet connection, you have to get a new I p. Address
the Internet control message protocols used for the exchange of control messages between hosting gateways and four diagnostic tools. It can also be a leverage for a lot of malicious behavior, including the Ping of Death.
I si m p redirect attacks ping scanning and remove procedure calls.
Think of death is a packet echo that is greater than the 65,536 points, which is the legal limit for a packet. If a packet back in the early days, if I pack it was said to AH, host that was braver than the legal limit would crash. That computer
redirected tax is a victim computer. Redirect sending information through an attacker's computer without them knowing
ping scanning. If the hose replies to a ping, that means it's an on and hosting drip and exists at that address.
Trace rap exploitation. This is used to map a victim's network and learn how the routers and the routing is laid out. And then remote procedure calls is the ability to allow for the executing off objects across hosts.
In today's lecture, we discussed I p Networking
This connection does not provide error free handling. It is known as a best effort connection. Is it a s s l
c c i d r or D u D p
If you said D u D P, then you are correct. Remember, UDP doesn't care if the packets actually get there or not. It is only concerned with transporting the packets as fast as it can.
Thanks for watching guys. I hope you learned a lot in this video and I'll see you next time