📡 Understanding IPv4: The Backbone of the Internet

🔍 What is IPv4 ?

IPv4 (Internet Protocol version 4) is the fourth version of the Internet Protocol (IP) and is responsible for identifying devices on a network using an addressing system. It enables communication between devices over the internet. 🌍

✅ Key Features of IPv4 :

• It is 32-bits addressing. 🖥️

• It is in number format we have to use number 0-255 between that.

• It is 4 octet and each octet is 8 bits separated by dot.

• Supports broadcast, unicast, and multicast communication. 📡📤

IP v4 is divided in five classes.

127.x.x.x is reserved for loopback addresses.

🌍 Public vs. Private IP Addresses

Note : The given range always apply to the starting of 1st octet only.

The range of Private IP Address.

Class a reserved 127.0.0.1 (loop back address ) rest of private IP address.

Important points :

Subnetting : Any large network divided in small small network. It is used for getting a higher routing efficiency and enhances the security of the network. It reduces the time to extract the host address from the routing table.

Types of subnetting:

Hub : Hub is a networking device which is used to transmit the signal to each port to respond from which the signal was received. Hub is operated on a Physical layer. In this packet filtering is not available. It is of two types: Active Hub, Passive Hub.

Switch : Switch is a network device which is used to enable the connection establishment and connection termination on the basis of need. Switch is operated on the Data link layer. In this packet filtering is available. It is a type of full duplex transmission mode and it is also called an efficient bridge.

Private IP Address : There are three ranges of IP addresses that have been reserved for IP addresses. They are not valid for use on the internet. If you want to access the internet on these private IPs, you must use a proxy server or NAT server.

Public IP Address - A public IP address is an address taken by the Internet Service Provider which facilitates communication on the internet.

NIC : NIC stands for Network Interface Card. It is a peripheral card attached to the PC to connect to a network. Every NIC has its own MAC address that identifies the PC on the network. It provides a wireless connection to a local area network. NICs were mainly used in desktop computers.

MAC address and IP address :

Points	MAC address	IP address
Purpose	Uniquely identifies a network interface card (NIC) within a local network, ensuring data packets are delivered to the correct device.	Identifies a device on a network, enabling communication across networks, including the internet.
Nature	A physical, hardware-level address assigned by the manufacturer and is typically permanent.	A logical, software-level address assigned to a device by an Internet Service Provider (ISP) or network administrator.
Example	00:1A:2B:3C:4D:5E	192.168.1.100
Use Cases	Used for communication across the internet.	Used for communication within a local network (LAN)

DHCP : DHCP is the Dynamic Host Configuration Protocol. It is an application layer protocol used to auto-configure devices on IP networks enabling them to use the TCP and UDP-based protocols. The DHCP servers auto-assign the IPs and other network configurations to the devices individually which enables them to communicate over the IP network.

FTP : FTP is a File Transfer Protocol. It is an application layer protocol used to transfer files and data reliably and efficiently between hosts. It can also be used to download files from remote servers to your computer. It uses port 27 by default.

ICMP : ICMP is the Internet Control Message Protocol. It is a network layer protocol used for error handling. It is mainly used by network devices like routers for diagnosing the network connection issues and crucial for error reporting and testing if the data is reaching the preferred destination in time. It uses port 7 by default.

Gateway : A gateway in networking is a network node that acts as a bridge between different networks, particularly those using different protocols, allowing data to flow between them.

Router : A device that forwards data packets to the appropriate parts of a computer network.

Conclusion :

IPv4 has been the backbone of the internet for decades, enabling global communication and connectivity.