Homebreadcumb forward arrow iconBlogbreadcumb forward arrow iconSoftware Developmentbreadcumb forward arrow iconWhat is Network Address Translation (NAT) in Networking? A Ultimate Guide

What is Network Address Translation (NAT) in Networking? A Ultimate Guide

Last updated:
6th Apr, 2023
Read Time
8 Mins
share image icon
In this article
Chevron in toc
View All
What is Network Address Translation (NAT) in Networking? A Ultimate Guide

NAT Network Address Translation is a networking firewall that enables your IP address to global computers. It’s a firewall that eradicates traffic between you and global devices.

 Before transferring your device’s information to the internet, NAT transforms your private IP address to a Public IP address for safe internet interactions. NAT acts as the first security firewall for hackers invading your system. 

Thanks to NAT, your IP address will become quite troublesome for these hackers to access. Although NAT is not the best cyber security, it certainly isn’t the worst. 

Decode all about this unique process in our comprehensive guide!

Ads of upGrad blog

Types of NAT

There are three types of NAT in networking, they are:

1. Static NAT 

The interconnection between two IP addresses is called Static NAT. Static NATs are useful when a private system needs to be accessed by the internet from outside. Static NATs need the local IP addresses and private area IP addresses to translate the information. This type of NAT is not often used because of its unregistered nature. Communication and translation through this will result in IP addresses not being publicly shared. The security of the Static NAT is considered a bit dangerous as your private IP address will be publicly visible to any and every individual.

2. Dynamic NAT 

A Dynamic NAT changes the device’s IP address whenever a local interaction occurs. It uses a technique called NAT pooling in which it maps a private IP address to a public IP address from a pool of public IP addresses. The pooled public IP addresses may vary as the location and available IP addresses may change. Dynamic NAT is used to translate unregistered IP addresses to smaller registered IP addresses. It connects you to a host of public IP addresses with a few limited registered IP addresses.

3. PAT 

Port Address Translation (PAT) is a mechanism that bands together many IP addresses into a singular public IP address. The best example of PAT is home internet routers, many devices are connected to the same network, but each is assigned a different IP address for the sake of discretion. PAT is used in a Local Area Network (LAN) environment to differentiate users accessing the internet. For the public, the IP address of LAN would be the same for everyone, but the internet provided by LAN would assign different IP addresses to every connected host.

Port Address Translation


What Are IP Addresses?

Internet Protocol (IP) address is a specific number assigned to your device having a network. These devices use IP addresses to interact with each other over the internet and other platforms. These IP addresses are also used to find the device’s location online. 

IP addresses can broadly be classified into the following types: Private, Public, Dynamic and Static.

1. Public IP address 

A Public IP address is an address connected to a network of addresses. All the connected devices to that network will have the same IP addresses. The best example of Public IP addresses is LANs.

2. Private IP address 

A Private IP address is a specific IP address that your networking device has. Every device, like smartphones, computers, tablets, and laptops, with a network, has a different IP address. Just like we humans have names to introduce ourselves, IP addresses are numbers to introduce a device.

3. Static IP address 

Static IP addresses are IP addresses that never change; it always remains constant. The advantage of a Static IP address is that when people connect themselves to you once, they can always find you over the internet. It is also called a fixed or dedicated IP address. 

4. Dynamic IP address 

Most devices use Dynamic IP addresses compared to Static IP addresses because of their nature. A Dynamic IP address always changes and never remains the same. When you browse on the internet, a dynamic IP address is provided for you, which changes every time. For the second time, when you browse the internet, you will see that your IP address will be changed.

Check out our free technology courses to get an edge over the competition.

The Security of NAT

NAT in networking is not a security system. But NAT acts as the first security firewall on the device. NAT ensures all incoming and outgoing translations are encrypted and inspected before being sent. NAT changes the public IP addresses to private IP addresses, thus, preventing anyone from accessing your device. NAT also acts as a privacy provider as it hides the work of your internal affairs from external affairs. 

Any device can’t just streamline your device in the presence of NAT, as NAT makes it difficult to pinpoint your access points and map your IP address. 

The most important fact to know about NAT is it does not provide security of any kind,

Firewalling, antivirus or even intrusion. NAT only provides privacy with your IP address and prevents any public IP address from hacking into your system.

The Security of NAT


The Address Types of NAT

With the question of “What is NAT” answered, there are a few more things to be answered. There are four address types of NATs, they are:

1. Inside Local Address 

All Inside addresses are usually private addresses. Inside Local Address means that a host is physically present inside the network as viewed through the inside network. Inside Local addresses are non-routable IP addresses.

2. Inside Global Address 

All Global addresses are usually public addresses. These Inside Global addresses are used for communication with the devices on the public internet. Inside Global addresses are re-routable IP addresses.

3. Outside Local Address 

Outside Local Addresses are private IP addresses which are non-routable by any means. Outside Local Address means that the host’s actual address is on the other side of the network. But we don’t know this for sure as the IP address can be the actual one or just another translated private address from another private IP address block.

4. Outside Global Address 

Outside Global Addresses are public IP addresses which are re-routable. Outside Global Addresses are used to communicate with other public IP addresses over the internet.

These were the four types of NAT addresses used for communication between public and private IP addresses.

Check Out upGrad’s Software Development Courses to upskill yourself.

Explore Our Software Development Free Courses


Advantages of NAT

Let’s explore some of the benefits obtained from NAT implementations!

  • The global IP addresses of NAT are anonymous, allowing millions of individuals to access the internet without any real private addresses.
  • NAT can use an IP address more than once without any disturbances in the network configurations.
  • NAT acts as a security firewall and hides the device’s IP address and location.
  • NAT can conserve IP addresses and thus reduce the need for more IP addresses to be created.
  • With the help of NAT, you can connect to millions of hosts on the internet with a few registered IP addresses.
  • The main advantage of NAT is that it reduces the depletion of IPv4 addresses.
  • NAT allows its users to use their private addresses and block the addresses provided by the Internet Service Provider (ISP).
  • The NAT firewall adds a layer of security in your router for the interactions between you and the internet.
  • NAT acts as an invisible shield between you and the traffic of online viewing.
  • NAT creates at least one inside and one outside interface that pools the public IP addresses and gives you a choice to choose from them.

Explore our Popular Software Engineering Courses


Disadvantages of NAT

While extending various benefits, NAT also has a few disadvantages. Let’s take a look.

  • Because of NAT, the router must filter all the public IP addresses for threats.
  • By using NAT, the feature of end-to-end addressing is lost, and many internet applications depend on it.
  • The Physical addresses an internet application uses fail to reach their destination as IPv4 changes its location many times.
  • The IPv4 communication takes time, and NAT acts as a delaying agent to it.
  • As the Private IP addresses are not traceable, NAT loses its end-to-end traceability advantage.
  • The IPsec is a network of communication between networks, and the use of NAT disturbs the tunnelling protocols of this software.
  • Some outside network services, like TCP and UDP, are disrupted unless the router of NAT is not configured for it.
  • Using NAT and translating information over the internet creates switching path delays.
  • For users like the IPv6 hosts, there is no security for them by using NAT.
  • NAT is known for its additional security systems, but it isn’t a security system and can only block minor intrusions.


NAT is a powerful process to maintain firewall security and assist any organisation in strengthening its network access. With improved privacy and boundary enforcement, NAT has been widely accepted to become a well know security measure. 

As the world is advancing to newer technologies and consistent intrusion by malicious traffic, the need for cyber security is increasing too. The best platform to educate yourself on cyber security is upGrad.

Ads of upGrad blog

Advanced Certificate Programme in Cyber Security is upGrad’s attempt to make learners aware of the growing demand to safeguard digital spaces while working on an expert-led curriculum that can help you take a leap in your career as well.

With topics like cyber security fundamentals, ethical hacking and NAT Network Address Translation, the program targets the audience of IT and Technological professionals with preferably prior knowledge of coding to expand their career in the fields of cyber security. 

Apply now to become a part of the dynamic industry!

Keerthi Shivakumar with strong and innovative strategies to promote the business brand and services globally.

Frequently Asked Questions (FAQs)

1What is NAT?

NAT is Network Address Translation which translates information through the router of Public IP addresses and Private IP addresses. It is used as a security measure to enforce boundaries and keep malicious public traffic at bay.

2What are the three types of NAT?

NAT can be applied using three different ways with the help of three different types of NAT, which include Static NAT, Dynamic NAT and PAT NAT.

3What's the main use of NAT?

NAT is used to map the location of Public and Private IP addresses. NAT‘s implementation as a network intermediary to keep outbound traffic away while regulating a set of public networks within an organisation to run under limitations.