Difference Between Public and Private IP Addresses?

IP Addresses have different classifications and there are many different types of IP Address available for distribution – Examples of different IP Addresses include static, dynamic, private and public. These types of IP Addresses have different functions and are distributed in different methods. When considering IP Addresses and internet security, it is important to learn the difference between Public and Private addresses – These are two very different types of address that serve different purposes.

at is a public IP Address?

A public IP address is an address that is assigned to a device that is connected to the internet. To connect to the internet, a device must have a unique IP address to allow other nodes and devices to locate it and establish a connection. A public IP address could be assigned to a web server, an email server, or even an individual’s personal computer.

Public IP addresses will be distributed and allocated initially via ICANN (Internet Corporation for Assigned Names and Numbers) – This organization is responsible for the creation of IP addresses and initially distributing them to secondary organizations. Public IP addresses are then distributed to such organizations as Internet Service Providers who finally distribute them to then end user.

Public IP addresses are unique, and can be searched for over the internet using tools such as the Windows command prompt utility or websites such as “What is my IP Address”.

What is a private IP Address?

A private IP address is assigned to a device within a closed network and is not readily available to search for on the internet. To facilitate the distribution of IP addresses within networks and organizations, private addresses were created. It is easier to understand a private IP address by explaining an actual scenario.

Let’s imagine that you have a home network – You have a desktop computer, a laptop, a smartphone and a tablet. These devices all connect to the internet through a central router. Instead of each device on your network being allocated with a public IP address, the only public IP Address you will use is assigned to the router.

A router will be assigned a public IP address, but will then assign a private address using the DHCP protocol to each device on your network. The devices on your network will communicate with each other using their private IP address, and the router will use its public IP address to facilitate communication over the internet. When connecting to the internet, your private IP addresses will remain hidden, and only the routers public IP address is visible.

The Zip Code analogy

A simple way to explain public and private IP addresses is to use the Zip Code analogy. A public IP Address acts in the same way that a Zip Code does – It directs communication to your network, in the way that a Zip Code directs mail to your business. A private IP address could be a specific department or team within your organization. The Zip Code (public IP address) can ensure that mail reaches your organization (network), but that mail would then have to be transferred to the correct department (using DHCP and private addresses!).