Difference Between Private and Public IP address

Both private and public IP addresses identify a specific computer in a network. But they still differ in many ways. A private IP address is an IP address that identifies a specific computer in a private network. But, a public IP address identifies a specific computer over the global internet.

Private addresses need not be unique universally. But, it has to be unique in their private network whereas, the public IP address has to be unique universally.

This section will discuss some more differences between private and public IP addresses. First, we will go through a difference chart. And then we will discuss the private and public IP addresses in brief.

Content: Private Vs Public IP Addresses

1. Difference Chart
2. What is Private IP Address?
3. What is Public IP Address?
4. Key Takeaways
5. Conclusion

Difference Chart

Basis of Differentiation	Private IP Address	Public IP Address
Network	Private IP addresses are used for computers in private network.	Public IP address are used for computers in global network.
Uniqueness	Private IP address need not to be unique in in the global network. But, it should be unique in their private network.	Public IP address should be unique in the global network.
Authorization	Public IP address should be unique in the global network.	Public IP address are provided only by Internet Service Providers (ISP).
Range	The range of addresses reserved for private addresses. 10.0.0.0 172.16.0.0 192.168.0.0	The addresses except private addresses are public addresses
Rout-ability	Private addresses are not routable.	Public addresses are routable.
Internet Access	Device with private IP addresses uses NAT router to communicate with the device in global network	Device with public IP address can easily communicate with any device in global network.
Cost	You don’t have to pay for using private IP address.	You have to pay ISP to have a public IP address for your system.
Retrieve IP address	You can retrieve your private IP address by typing "ipconfig" on command prompt.	You can retrieve your public IP address by typing "my IP address" on a search engine like Google.

What is a Private IP Address?

A few blocks of addresses were reserved as special addresses in classful addressing. The classless addressing also adopts these special addresses. Among these special addresses, some range of addresses were reserved as private addresses.

Private addresses are allocated to the computers in a small network. It helps in establishing internal communication between the computers in a private network. The computers in a private network cannot access the internet.

Because the data packets with a private IP address in their destination address field are not routable. It means if the router receives a packet with the private IP address in its destination address field, it does not forward it to any other network.

The range of addresses reserved for private IP addresses are:

• Block form class A, 10.0.0.0/8 has 16,777,216 number of private IP addresses.
• A Block from class B, 172.16.0.0/12 has 1,047,584 number of private IP addresses.
• Block form class C, 192.168.0.0/16 has 65,536 number of private IP addresses. Generally, private addresses from Class C is used for computers in a private network.

Assigning private addresses to computers in the private network does not need authorization. And you don’t even have to pay to use private IP addresses.

Well, if the computer with a private IP address wants to access the internet it requires the NAT router. NAT router maps multiple private IP addresses to a public IP address, to access the internet.
NAT router maintains a translation table that helps in mapping the address.

You can check the private IP address of your computer by typing “ipconfig” in the command prompt. Private IP addresses assigned to the computers in a private network differ in a uniform way.

What is Public IP Address?

The public IP address is allocated to the computers in a global network. Unlike a private address, a public IP address of every computer in a universal network must be unique. So that, we can uniquely identify a specific computer in a global network.

An Internet Service Provider (ISP) has authority to issue a public IP to a computer in the global network. You have to pay ISP for issuing the public IP address for your computer.

Data packets with a public IP address in their destination address filed are routable. So, a computer with a public IP address can easily communicate in a global network.

To know your system public IP address just type “my IP address” on any search engine like Google. As the range of addresses given below is the private IP addresses:

• Block form class A, 10.0.0.0/8 has 16,777,216 number of private IP addresses.
• A Block from class B, 172.16.0.0/12 has 1,047,584 number of private IP addresses.
• Block form class C, 192.168.0.0/16 has 65,536 number of private IP addresses.

The IPv4 addresses excluding the above private addresses are the public IP addresses. If IPV6 completely replaces IPV4, there is no need for private IP addresses. IPv6 has an enormous range of addresses. And it can provide public IP addresses to all the devices that need internet access.

Conclusion

We may not use private IP addresses future. As IPV6 addresses have a huge range of addresses. IPV6can issue a public IP address for all devices that want to access the internet.