 Hello. Hi, everyone. I am Sanjay Gupta. I welcome you on Sanjay Gupta Tech School. Welcome, Sumit. So, today we have day two of Salesforce and cybersecurity bootcamp. So, before starting this session, I just want to clear you guys. Lots of people are asking this cybersecurity bootcamp is related to Salesforce or not. So, let me clear. It is directly related to Salesforce. In Salesforce, there is a job role which is related to cybersecurity. So, like other than admin, development, QABA, project manager, architect, if you want to become a cybersecurity expert, so you can learn whatever Sumit is delivering in this bootcamp. And basis on that knowledge, you can also apply as a cybersecurity expert in Salesforce ecosystem. Right? So, it makes it clear like it is related to Salesforce and I will share some insight. So, today I shared one tweet in our telegram group which directly shows like more than 80,000 jobs are available currently in Salesforce ecosystem for this job role. Okay. So, with this note, I am inviting Sumit for day two session. So, he will be sharing all the insights for today. Go ahead, Sumit. Welcome again on this cybersecurity bootcamp day two. So, my name is Sumit Jain and today I will be talk about how the network work, how you will connect the network, what are the types of network we have. So, before we begin, let me introduce myself. My name is Sumit Jain and I am an ethical hacker and cybersecurity expert. Currently, I am working as a red team member in Cinec and Pentagov. Apart from that, I am working as a senior security specialist at JITRO Networks, the company located in Jaipur, India. I have experience of 10 plus years in this domain. Previously, I am a guest instructor at CDTS Center Detective Training School. And right now, I am helping students, researchers and professionals to build their career in cybersecurity stream. So, if you like our content, we are delivering, we are making. So, please subscribe and follow and share these YouTube channels. My YouTube channel name is Cyber Security Zone and you are seeing me live on this Sanjay Gupta Tech School. Please share or review or feedback about this bootcamp, what you want to me deliver. And you can follow me on these below platforms as well. You can find the important links in the video description. So, begin with that to today's topic. So, today I will be talk about how computer network work. So, what is computer network? Computer network is a group of computer connected with each other through wires, optical fibers or optical links, so that various devices can interact with each other through a network. So, when you connected various computers or devices with each other through any devices, any components of the network, like wires, like Wi-Fi modem or Wi-Fi router, hub switch, then you are transmitting the data in both systems and then we say that we have a network, we are in a network. The aim of the computer network is sharing of resources among various devices. The devices can be your computers, your servers, your networking devices as well. In case of computer technology, we have several types of network that can vary from simple to complex level. So, first we have to understand what network is, what computer network is and what are the devices we use to create a network, how to manage a network and what are the components we have for creating a network. So, what is network? Network is if we attach, if we connect two devices, let's suppose we have two devices and we connect those two devices with the wire. Wire can be different, wire can be also various types of wire we have. So, this is your computer one, let's say this is user one and this is user two. So, we have two users and I connected the users with the wire technology and if they are sending or receiving data, if these two systems are transmitting the data with each other, then we can say transmitting the data. So, data is transmitted from one computer to another computer, one is sending and other one is receiving, then we can say they are in a network, these both systems are in a network. So, if a system is a network, it have to be the transmission mode is open, they have to transmit the data and the data transmission is done by packets. So, what are the packets? So, everything you shared on a computer network, everything you shared on internet, it will be done by packets. The amount of data you will be shared, if you have something like you have a text format, you have a PDF document, you have an audio file, you have a video file, any amount of data, it can be sent using packets. So, packet is something, packet you can say packet is small units of data, small units of data. So, let's take one example, if we have one GB of data, then it can be divided into multiple packets when we send the both files into internet or another computer, the packets are, packets the term which is sent by. So, packet is something which is small units of data which is carried by the network. So, if two systems, if we have two systems like one is this system and the other one is this, they are sending or receiving data using some network components, for network components, we have a test developer and they are transmitting the data, then we say this is a network. So, hope you understand this, so network will be used to share data, network will be used to receive data and we can use network for security purpose, we can use network for software and hardware sharing, we can use for communication speed. So, network can be used for multiple purposes and for this we have network devices. So, we have network components to create this network, network components. So, what is the network components, the devices, the wires we use to create a network are called network components and some of the network components we use is NIC. NIC refers to network interface card. NIC is refers to network interface card and NIC is a device that can help the computer to communicate with another device. So, the NIC is a device that can help the computer to communicate another device. The network interface card contains a hardware address. So, basically the NIC you have in your computer have an address which is called hardware address. So, it have a hardware address. So, when you purchase a computer, so you have a communication medium. If I explain in a simple way, if you connected your internet using Wi-Fi and if you are connecting using your internet with a wire, we have network interface card. The NIC is come with your computer and this is the interface, this is the component which is used to create a network, which is used to transfer your network, which is used to create, which is used to supply your internet. So, the NIC network interface card, it can help your computer to communicate with another device. It has a hardware address which is called MAC address. So, you have heard about the MAC addresses we have in your computer system. So, the MAC address is for NIC. NIC have that MAC address. So, we have two types of NICs. We have two types of NIC. One is wireless NIC and the other one is wired NIC. Wireless NIC and the other one is wired NIC. So, I hope you understand this, the wireless NIC or the modern computers are using the wireless technology. So, in wireless NIC, a connection is made using the antenna that employs the radio wave technology and in simple way you can understand if you have a laptop, you are connecting your internet with the Wi-Fi. So, the Wi-Fi has the wireless NIC in it and if you are using, if you have older computers like CRT monitor, you have to connect the internet using wire, which is called Ethernet wire. So, the wired NIC will be used to connect internet. So, the NICs are the main component to connect the internet and this will be your component to communicate with another device. So, the wireless NIC, a connection is made using the antenna that employs radio wave technology and what will the wired NIC will use? The cables are used in wired NIC. Cables use the wired NIC to transfer the data over the medium. The medium you want to transfer your data, basically you want to send your packets from your device to another device or in the internet. So, you will use internet and for using internet, you will use wired NIC. So, we have two types of NIC in our computer system, one is wireless NIC and the other one is wired NIC. They both have an address which is called MAC address. They both have an address which is called MAC address. So, if we are using a computer, a laptop, so we have both NICs, so we have two MAC addresses in our system. And if you want to check what is the MAC address of your system, you can open your CMD which is command prompt. You can open it by pressing windows plus R keys and then type CMD. After this, your CMD will be opened and if you run this command like ipconfig slash all, then you can have your MAC addresses. What are the NICs, what types of NICs in your system have? You have your MAC addresses. The MAC addresses are also known with some of the names which is physical address, hardware address, network address. So, when you run this command, you will find physical address and the physical address is also known as MAC address. So, you have your MAC address of your devices. So, the first network component is NIC which is called network interface card that can help your computer to communicate with another devices. The NICs have an address which is called MAC address and we have two types of NIC, one is wireless NIC and the other one is wired NIC. For modern computers, these two are available but if you are using a monitor computer or an old computer, you have only one NIC in your system which is wired NIC. We have a third NIC as well for modern day computers which is for Bluetooth. So, Bluetooth is also with the wireless NIC so I am not writing it here but we have different address for the Bluetooth NIC. So, NIC is a chip, a hardware devices which will come when you buy a computer, it can be implemented with your motherboard. So, we can replace this NIC if you want to change our MAC addresses but this will come when you buy a system. So, moving on to the other network components, the second network component we have is a hub. Hub is a device, basically a central device that can split your network connection into multiple devices. So, when we use hub, a computer request for information from a computer and it can send to the hub, hub distributed this request to all interconnected computers. So, hub is a central device. We are talking about all the network devices we have. So, we have NICs, we have hub, router, switches, bridges, repeater and cables and connectors. So, I am writing here what is the network components we have. So, hub is a central device that splits the network connection to the hub and hub will distribute the request to all the interconnected computers. The next device we have is switches. Switches is something like hub that can work differently. So, let me just explain everything, whatever is written once again. There was some internet issue. Okay. So, basically we are learning about network components. So, the one network component we learn is NIC. NIC is a hardware device which can come with your computer. That was good. Just start with the hub again. Okay. So, the hub is a central device and it can split your network connection into multiple devices. Like if you have a network of 10 computers, we installed hub and if you want to request some data from one computer and we have a network of 10 computers. So, we use hub. So, hub can split our network connection into multiple devices and can request from another devices. And hub can also distribute the request to all the computers. Whatever computers have, whatever computer have those information will send it out to your desired information. The other device is switches. So, switches also a network device that group all the devices over the network to transfer the data to another devices. So, switches are better than hub because it does not broadcast the message over the network. See, if we use hub in a network, whenever a message is generated, it will broadcast over the networks. All the computers will listen the information computer is asked. But if you use switches, the information, the message, the request will not broadcast over the network. It sends the message to the device which is blown to. It can only send the message. Whatever device you want the information to. So, switch is better than hub. So, we will use a switch in our network to create a network. So, you can write switch is also a network device that group all the devices over the network to transfer the data. Switch does not broadcast the message over the network. It sends the message to the device it belongs to. So, we can say the switch sends the message directly from source to destination. But hub will send the message with entire network communication. The other components we have is cable and connectors. The cables you are known as Ethernet cable. So, the cables are also three types of cables we use to build a network. One is twisted pair cable. It is a high speed data transmit cable that can transmit your data with the speed of 1 gbps per second and more. So, if you are using a network in your home network, so we have this twisted pair cable. So, it is a high speed cable that transmits the data over 10 1 gbps. One gbps per second or more. The other cable we have is coaxial cable. This cable is used for TV installation mode or like TV installation cable. This cable is more expensive than twisted pair cable. But it provides the more speed, more high speed for data transmission. So, if we have a connection, if we want more speed then we use this type of cable. Coaxial cable is expensive twisted cable but high speed, high data transmission speed. And the next one we have is fiber optic cable. So, this type of cable can also be used to create a network. And if we use fiber optic cable it will transfer our data with light beam with the speed of light beam. So, in model era the fiber optics or cables are used for creating a network for sharing a network. That can transmit the data using light beam. Also, it provides higher data transmission speed as compared to other cables. It is more expensive as compared to other cables. So, we don't use this cable at our home. We use this cable to build a server. And if you are using a company, if you are having a large network then we use this type of cable. So, we have this network component cable and connectors. The connectors are those which connect the cables. So, if you are using a twisted pair or coaxial cable we use RJ45. This is the connector type we use for built-in network RJ45. Next. So, there is one question. Chandan is asking what is the difference between broadcast and send messages? Broadcast is something when you transmit a message over the network. So, the message is seen by the other computers. So, it will be broadcasted over the network. Like I will stream a cricket match live. So, it will be broadcasted over all the networks, all the connected devices. And if you are using a WhatsApp chat, the messages are seen and received by the senders and receiver. So, the broadcast messages will be shared with all the connecting devices and the personal messages are shared with the devices they connected. There is one more question. Please repeat about RJ45. So, RJ45 is a connector type. If I want to share you, let's see the image of RJ45. This is RJ45. The connector we use to create a cable. This is called RJ45. And we have different types of connectors or connecting different types of cables. Like if you are using a telephone line, we have to use RJ11 connector. And if you are connecting internet, you use RJ45. And we have various types of connectors for various types of wires. So, if you are using fiber optic, we have a different types of connector like RJ11W and RJ21. So, different types of connectors are in the market to connect different types of network cable. And the cables are three types. The other network component we have is router. So, router is a device that can connect the LAN, local area network to the internet. So, router is mainly used to connect the network or connect the internet to multiple computers. So, if you are using your Wi-Fi, so have you heard about routers, Wi-Fi routers? So, the routers in your home, you are connecting to, which is distribute the network, which is a main component to connect the internet to multiple computers. So, if we want to distribute our internet, we have to use a router modem. We have to use a device which is called router. And it can help you to distribute your internet connection with multiple computers. So, router is a device that connects the LAN to the internet. The router is mainly used to connect the networks, connect the internet to multiple computers. The next network component we have is modem. So, if you are ever heard about the modem, we have a modem for distributing network like Airtel modem, Geo modem. So, the modem is something that can modulate or demodulate your signals and change your analog signals to digital signals. So, a modem is a separate part of PC. It can be found on the motherboard. So, modem is not integrated with your computer motherboard. So, modem connects the computer to the internet over the telephone line. So, if you are using a broadband connection like DSL, so you have to use a modem that can separately connect your telephone line as well as your internet. So, the modem connects the computer to the existing telephone line. A modem is not integrated with the computer motherboard. So, why we use a computer network? Because we have to share our resources. What we want to download, we have to share some programs for various devices on the various devices. So, we have to use these network components to create or to manage a network. Move on. So, hope you all understand with the computer network. So, computer network is a group of computers connected with each other through wires, optical fibers or optical links, so that various devices can interact with each other through a network. For those, we have network components. Using network components, we can create a network. The aim of computer network is sharing resources among various devices and the data will be sent by using packets. Packet is something which is small units of your data. So, if you shared a large file, the various packets are divided and they can be sent out through your network. So, the components we have is NIC, network interface card or network interface controller, hub, switches, routers, modems, cables and connectors and repeater. So, repeater is a device which can repeat your signals. Like if you are sending your data from a short distance to long distance, your signals can be lost throughout the medium, throughout the transmission. So, we use a device called repeater which can repeat your signals and your signal strength will be flexible. Okay. Move on. The computer network architecture. We have two types of network architecture are used to create a network to establish a network. One is P2P network and the other one is server client network. P2P network is called P2P network and server client network are for those who are connecting their devices and controlling some devices over a network. So, let's understand what is P2P and what is server and client. P2P network is something when the connected computers have full privileges and full rights to do what they want on a network. So, we use P2P network and if some computers are controlled by some computers or other computers which is called server and client network. So, P2P network is a network in which all the computers are linked together with equal privileges, responsibilities for processing the data. This can be useful for creating a small environment, usually for 10 computers and P2P network has no dedicated server which is controlling all the computers. So, if I will create a diagram for you. So, this will be our P2P network. So, in P2P network, we have multiple devices like this. This is a device, this is a computer device. We have a four devices connected a internet connected a medium connected in an end network. So, this device is connected with this, this device is connected with this. They are connecting with each other and they are sending or receiving data. So, this network is P2P network where all the computers have equal rights. There is no server to control the computers what he want to do and what the server wants, server grants you permission to do the things on the internet. P2P network in P2P network all the computers have equal rights and privileges like all the computers can download whatever the things they want. All the computers can upload whatever the things they want to upload and there is no server to control the network. And it can be useful for creating a small environment usually for 10 to 20 computers. So, the advantages of this network are it is less costly for the disadvantage of P2P network. So, in the case of P2P network, it doesn't contain the centralized system. Therefore, it cannot backup the data as the data is different in different locations and it has also security issues as the devices is managed by itself. So, for a larger system we will not use this P2P network, we use server client network. So, P2P network is something when all the connected devices have equal rights, equal privileges to share the network resources to share the data in a network. So, it is called P2P network. So, Sumit actually there was some internet issues. So, I think the last thing advantage of P2P is needs to be repeated. Okay. So, the advantage of P2P network is because it doesn't have any dedicated server. So, it is less costly to build on and if in this P2P network if one computer stops working, the other computers are working as fine. So, we don't have any errors in our network system. So, P2P is also used for creating a small environment and it is easy to set up and maintain because each computer manages itself. There is no other server or computer managing the computers. So, every computer is managing itself. So, it is easy to set up and maintain. And the disadvantage of this P2P network is one is it has security issue because of the devices managing itself. So, we have security issues. Also, the P2P network cannot backup the data as the data is different in different location. For both disadvantages, we have server client network. So, if in your network, a device is controlling all of your computers is called server and the devices controlled by devices controlling those systems are known as clients. So, in client server model, a computer is controlling all the resources for the central controller is known as server. Central controller is known as server while all other computers in the network. So, in server client network, a network model is designed for end users called clients to access the resources such as videos, the data you want to download from internet from central computer known as server. Like if you are visiting a website, the data you are downloading, so the Google has a server and you are the client. So, we have a server client network while visiting by using a website. So, the server performs all the major operations such as security and network management and server is also responsible for managing all the resources such as files, directories, printer and all the clients can communicate with each other through a server. The clients cannot directly communicate with each other without the server, so server is controlling the clients. So, if a client wants to send some data to client 2, then it first send the data to the server for the permission and server sends the permission to client 1 to initiate the communication with the client 2. So, we have client server network if we are managing controlling by some computers or a server. So, this is called server and client network. So, what are the advantages of client and server network? So, server and client network is centralized system so we can backup the data easily and we can improve the overall performance of the whole system, whole network, security is better than the P2P network and it can also increase the speed of sharing resources. And without the disadvantage, it is expensive because it contains very large memory and if the server goes down, the whole network will go down as well. But this problem we don't have in our P2P network. So, we have two types of network in our computer network, which is one is P2P network and the other one is server and client network. So, hope you understand this. We will continue this network session from tomorrow as well. And we have computers network types from geographical area and also I want to tell you about the network topologies. So, and what is the IPs? How IPs can be delivered to you? How you can assign IP in a network? How to check IP? And we will learn something more about the NIC as well because it will be useful in our security systems. And IP is something we have to understand very quickly and very well because IP is something you need to explore in your security bootcamp. So, thank you guys for joining this session and we will continue from tomorrow. So, can we take some questions? Okay. This I think we already answered. So, from here if you can see questions and answers. RG connector used with CAT 6 or CAT 5 cable. Currently it is used with CAT 5 cable and Chandan is asking what is meaning of light beam. So, Chandan, light beam is something when you are transmitting the data with the speed of light. So, this is called light beam. So, I just asked them like explaining speed. So, they are saying it is good. So, that was it. Here he is asking about access point. Access point is also a network device which can, which will be your network will access. So, when we learn about the IP address, we will discuss this access point. Using access point you can assign your IPs. You can manage your network difference between modem and outer. So, Chandan modem is something which can modulate or demodulate the signals. Your signals from the servers are coming in the analog frequency and your device can only read digital frequency. So, the modem is device which can demodulate or modulate or change the signal frequency from the readable to computer readable. So, can computer can read and router is a device who can use to create internet to connect multiple computers in a network. What is server? Server is something which is controlled all the clients in a network. And it is also responsible for managing security and assigning IP addresses. This one. So, what is the real time example of P2P network? Where do we use this type of network? If you are using your phone connection, if you are connecting with Wi-Fi, if you are using internet, then this is example of P2P network. Where all the devices, all the computers, all the modems you connected in your network can access or can send, can create whatever they want. There is no server to controlling you. This is like difference between IP and MAC address. So, UMKOKH IP address is assigned by the ISP internet service provider. It will be assigned on your network. IP address is assigned to your network and MAC address is address for your devices. So, if you are using a network and to create a network, we use devices. So, the MAC address is for the device address and IP address is for your network address. Thank you, Arya. So, guys, if you have more questions you can ask or like I would request just go through the recording once again so that you can just recap all the concepts. And yesterday I shared one deck in the telegram group. So, the slides will be adding to that deck also. Yes, IP can be automatically and manually assigned. The public IP will assign automatically by the ISP server and the private IP you can assign automatically and you can assign with manually as well. Okay, so I think we can wrap today's session here only. So, guys, please recap both the sessions day one, day two and all the study material we will be sharing in the telegram group. And if you see this session tracker, so here in the session tracker, like some prerequisite thing is available and here that slide link is available. So, if you open it, so here you will find all the theoretical aspects. And this is trailhead link here also you will find some things. Okay, so go through with this and all the recordings will be available here. So, anytime you can just quickly watch whatever we have explained like Sumit explained here. Okay, so, Sumit, I think there is one more question. PPOE network, Anil, when we discuss about the IP address, you can understand what is PPOE network. Yeah, yes, Anis, we'll be providing the notes. So, just follow that PPD which I shared. So, there all the documentation will be available. Okay, guys, so thank you so much for joining today's session and we'll see you tomorrow. Thank you. Bye everyone. Bye everyone. Thank you so much for joining.