Private vs Public IP

 An IP address (Internet Protocol address) is a unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves two main functions:

1. Network Interface Identification: It identifies the device on the network.
2. Location Addressing: It helps in locating the device within the network.

There are two types of IP addresses:

• IPv4: Uses a 32-bit address scheme allowing for over 4 billion unique addresses.
• IPv6: Uses a 128-bit address scheme, providing a vastly larger number of addresses.

IP addresses can also be categorized as:

• Public IP addresses: Used to identify devices on the internet.
• Private IP addresses: Used within a private network

Public IP Addresses

• Definition: A public IP address is a unique address assigned to a device that is directly connected to the internet. It is globally unique and can be accessed from anywhere in the world.
• Purpose: Public IP addresses are used to identify devices on the internet, allowing them to communicate with each other. For example, when you visit a website, your device uses its public IP address to request data from the website's server, which also has a public IP address.
• Assignment: These addresses are assigned by Internet Service Providers (ISPs) and are registered with the Internet Assigned Numbers Authority (IANA) to ensure they are unique.
• Example: An example of a public IP address is 203.0.113.1.

Private IP Addresses

• Definition: A private IP address is used within a private network to identify devices. These addresses are not routable on the internet and are used for internal communication within a local network.
• Purpose: Private IP addresses allow devices within the same network (like a home or office network) to communicate with each other without using the internet. They help conserve the limited number of public IP addresses.
• Assignment: Private IP addresses are assigned by network administrators or automatically by routers using DHCP (Dynamic Host Configuration Protocol).
• Example: Examples of private IP address ranges include:
• 192.168.0.0 to 192.168.255.255
• 172.16.0.0 to 172.31.255.255
• 10.0.0.0 to 10.255.255.255

Key Differences

• Visibility: Public IP addresses are visible on the internet, while private IP addresses are only visible within a local network.
• Accessibility: Devices with public IP addresses can be accessed from anywhere on the internet, whereas devices with private IP addresses can only be accessed within the same network.
• Security: Private IP addresses provide an additional layer of security since they are not exposed to the internet, reducing the risk of external attacks.

NAT (Network Address Translation)

To connect devices with private IP addresses to the internet, routers use a process called Network Address Translation (NAT). NAT allows multiple devices on a local network to share a single public IP address for accessing the internet. This helps in conserving public IP addresses and adds a layer of security by hiding internal network structures.