Structure and Types of IP Address

An IP address (Internet Protocol address) is a unique numerical identifier assigned to each device connected to a network. It allows devices such as computers, smartphones, servers, and IoT devices to identify each other and communicate over the Internet or a local network. Every data packet sent across a network contains both the source and destination IP addresses to ensure correct delivery.

Structure of an IP Address (IPv4)

An IPv4 address is a 32-bit number, usually written in "Dotted Decimal" format. It consists of four numbers (octets) ranging from 0 to 255, separated by dots.

Example: 192.168.1.15

The address is split into two logical parts. The split depends on the Class or Subnet Mask:

1. Network ID: Identifies the "Street" (The network the device belongs to).
2. Host ID: Identifies the "House Number" (The specific device on that network).

Versions of IP Address

There are two main versions of IP addresses currently in use:

IPv4 (Internet Protocol Version 4)

• Address size: 32-bit
• Format: Decimal (e.g., 192.168.1.1)
• Total addresses: 4,294,967,296
• IPSec: Optional
• Widely used but facing address exhaustion

IPv6 (Internet Protocol Version 6)

• Address size: 128-bit
• Format: Hexadecimal (e.g., 2001:db8::1)
• Total addresses: 3.4 × 10³⁸
• IPSec: Mandatory
• Designed to solve IPv4 address shortage

Types of IP Addresses

There are 4 types of IP Addresses- Public, Private, Fixed, and Dynamic. Among them, public and private addresses are derived from their local network location, which should be used within the network while public IP is used offline.

• Public IP Address: A public IP address is an Internet Protocol address, encrypted by various servers/devices. That's when you connect these devices with your internet connection. This is the same IP address we show on our homepage. So why the second page, well, not all people speak the IP language. We want to make it as easy as possible for everyone to get the information they need. Some even call this their external IP address. A public Internet Protocol address is an Internet Protocol address accessed over the Internet. Like the postal address used to deliver mail to your home, the public Internet Protocol address is a different international Internet Protocol address assigned to a computer device. The web server, email server, and any server device that has direct access to the Internet are those who will enter the public Internet Protocol address. Internet Address Protocol is unique worldwide and is only supplied with a unique device.

• Private IP Address: Everything that connects to your Internet network has a private IP address. This includes computers, smartphones, tablets and Bluetooth-enabled devices such as speakers, printers, or smart TVs. With the growth in IoT devices, the number of private IP addresses we have at home is also increasing. Routers need a way to identify these problem separately, and most things need a way to know each other. Therefore, routers generates private IP addresses that are unique identifiers for each device that separates the network.

• Static IP Address: A static IP address is an invalid IP address. Conversely, a dynamic IP address will be provided by the Dynamic Host Configuration Protocol (DHCP) server, which can change. The Static IP address does not change but can be changed as part of normal network management. Static IP addresses are incompatible, given once, remain the same over the years. This type of IP also helps you get more information about the device.

• Dynamic IP address: It means constant change. A dynamic IP address changes from time to time and is not always the same. If you have a live cable or DSL service, you may have a strong IP address. Internet Service Providers provide customers with dynamic IP addresses because they are too expensive. Instead of one permanent IP address, your IP address is taken out of the address pool and assigned to you. After a few days, weeks, or sometimes even months, that number is returned to the lake and given a new number. Most ISPs will not provide a static IP address to customers who live there and when they do, they are usually more expensive.

Types of Website IP Address

• Dedicated IP address: A dedicated IP address is one that is unique for each website. This address is not used by any other domain. A dedicated IP address is beneficial in many ways. It provides increased speed when the traffic load is high and brings in increased security. But dedicated IPs are costly as compared to shared IPs. 
• Shared IP address: A shared IP address is one that is not unique. It is shared between multiple domains. A shared IP address is enough for most users because common configurations don't require a dedicated IP. 

Classful IP Addressing and Their Uses

IPv4 addresses were traditionally divided into five classes:

Class A

• Range: 1.0.0.0 – 126.255.255.255
• Network bits: 8
• Host bits: 24
• Use: Large networks
• Example: Government organizations
• 127 is reserved for loopback

Class B

• Range: 128.0.0.0 – 191.255.255.255
• Network bits: 16
• Host bits: 16
• Use: Medium-sized networks
• Example: Universities

Class C

• Range: 192.0.0.0 – 223.255.255.255
• Network bits: 24
• Host bits: 8
• Use: Small networks
• Example: Home and small businesses

Class D

• Range: 224.0.0.0 – 239.255.255.255
• Use: Multicast communication
• Example: Video streaming

Class E

• Range: 240.0.0.0 – 255.255.255.255
• Use: Experimental and research
• Not used for public networking

IP Address Classification Based on Operational Characteristics

• Broadcast addressing: The term 'Broadcast' means to transmit audio or video over a network. A broadcast packet is sent to all users of a local network at once. They do not have to be explicitly named as recipients. The users of a network can open the data packets and then interpret the information, carry out the instructions or discard it. This service is available in IPv4. The IP address commonly used for broadcasting is 255.255.255.255
• Unicast addressing: This address identifies a unique node on the network. Unicast is nothing but one-to-one data transmission from one point in the network to another. It is the most common form of IP addressing. This method can be used for both sending and receiving data. It is available in IPv4 and IPv6. 
• Multicast IP addresses: These IP addresses mainly help to establish one-to-many communication. Multicast IP routing protocols are used to distribute data to multiple recipients. The class D addresses (224.0.0.0  to  239.255.255.255) define the multicast group.
• Anycast addressing: In anycast addressing the data, a packet is not transmitted to all the receivers on the network. When a data packet is allocated to an anycast address, it is delivered to the closest interface that has this anycast address.