Prithivi Raj Kumar
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NAT ?  Natting ! Why do we need it?

NAT ? Natting ! Why do we need it?

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Prithivi Raj Kumar
·Oct 19, 2021·

2 min read

Firewall Team - Natting is done from our end.

System Engineer - What the heck is Natting?

What is NAT?

NAT - Network Address Translation.

NAT is the service used in routers. Its main purpose is to translate one set of IP address to another set of IP address.

NAT helps to preserve the limited amount of Public IPv4 address that we have available around the world

Why do we need NAT?

If we need to know the reason why we need NAT, we need to revisit the history of the IPV4 address.

In the Year 1980. Ipv4 is created, Network engineers didn't anticipate the internet booming,

Even though there are 4.3 billion Ipv4 public addresses are available, It is not suffice to assign public addresses to every network device.

To solve this problem, they came with the solution

So, They created a Private IP address and Network address translation (NAT )

Two Types of IPv4 address

Public Address

Private Address

Public Address

A device must have a public address in order to communicate to the internet

There are 4 Billion public Ip addresses are registered on the internet


Private address

private Ip addresses are not publicly registered

We cannot directly access the internet with a private address


We can ask our ISP provider to provide with us the public address for every device we have, but it leads to cost expensive and unnecessary.

If people started owning their public IP address, we would run out of public ipv4 addresses already.


Our device is assigned with a private address, whenever it needs internet access, our NAT Translated the private Ip address to one public address which we have assigned and vice versa.

This is what NAT does!

It translates the set of IP address into another set of IP address

NAT Translate -

private to public

Public to private


Experts words.

In the future, we won't need NAT or a private address. This is because the new generation of IP address called IPv6 address.

With IPv6, every single device in the world will have its own public address. So there is no need for IP address translation

IPv6 addressable to produce over 340 undecillion IP address

IPv4 Capacity - 4,294,967,296

IPv6 Capacity - 340,282,366,920,938,463,463,374,607,431,768,211,456

Reference :

Note - If you found any discrepancy in the above information, kindly write to

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