What is Ipv4 Address ? [ Types And Example ]

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An IPv4 address is a unique identifier that a device uses on a network that follows the Internet Protocol (IP) version 4.  Think of it as a house address in the digital world. It allows devices to find and communicate with each other on the internet.

An IPv4 address is made up of 32 bits, typically written in a format called dotted decimal notation. This format breaks the 32 bits into four groups of 8 bits each, separated by periods. Each group, also called an octet, can have a value between 0 and 255. For instance, 192.168.1.1 is a valid IPv4 address.

IPv4 addresses play a crucial role in enabling communication across the internet.  However, due to its limited address space, IPv4 is being gradually replaced by a newer version, IPv6, which offers a much larger pool of unique addresses.

Types of IPv4 addresses include:

1. Unicast: 

An IPv4 address that identifies a single network interface on a host and allows communication between that host and other individual hosts.

2. Broadcast: 

An IPv4 address used to send data packets to all devices within a specific network segment. Broadcast addresses end with ".255" in each octet.

3. Multicast: 

An IPv4 address used to send data packets to a specific group of hosts that have joined a multicast group. Multicast addresses are identified by specific address ranges.

Example of an IPv4 address: 192.168.1.100

In this example:

 Each group of numbers separated by a period (.) is called an octet.

 Each octet ranges from 0 to 255, representing 8 bits of information.

 IPv4 addresses are typically written in decimal form, with each octet represented by a number ranging from 0 to 255.

 The example address, 192.168.1.100, is a common private IPv4 address used within local area networks (LANs).

Diving deeper into IPv4 addresses:

Structure: 

As mentioned earlier, IPv4 is a 32-bit number divided into four octets (8-bit sections). We usually see them represented in dotted-decimal notation, for example, 10.0.1.254. Each octet can range from 0 to 255.

Network and Host Parts: 

An IPv4 address is further divided into two parts: the network part and the host part. The network part identifies the specific network a device belongs to, while the host part identifies the individual device within that network. The division between these parts is determined by a subnet mask, which is another dotted-decimal notation that defines how many bits belong to the network and how many to the host.

Addressing Limits: 

With 32 bits, there's a limit to the number of unique IPv4 addresses available (around 4.3 billion). Due to the massive growth of the internet, we've reached a point where IPv4 addresses are scarce. This is why IPv6, with a significantly larger address space, is being implemented. 

Classes: 

IPv4 addresses were historically divided into classes (A, B, C) based on the leading octet, which determined how many bits were allocated to the network and host parts. These classes offered a way to assign addresses based on network size. However, this system wasn't very efficient and is no longer strictly followed due to address depletion.

Public vs. Private: 

IPv4 addresses can be public or private. Public addresses are routable on the internet, meaning devices with these addresses can be directly accessed from anywhere on the web. Private addresses, on the other hand, are reserved for internal networks and aren't routable on the public internet. 

Common private address ranges are 10.0.0.0 - 10.255.255.255, 192.168.0.0 - 192.168.255.255, and 172.16.0.0 - 172.31.255.255.