What Is NAT? Network Address Translation Explained

In theory, if you have multiple devices that need to access the Internet, they would each require a unique IP address. However, with NAT, users only need a single address. NAT enables one unique IP address to represent an entire group of computers, which keeps the Internet functioning smoothly. In this article, we'll explain all you need to know about NAT - what network address translation is, what it does, how it works, and other additional information.

What is NAT in networking?

NAT, or network address translation, is the process of translating one set of addresses (usually an IP address) to another so as to provide Internet access to the local hosts. IP addresses are the cornerstone of Internet communication; NAT acts as an agent to interconnect two devices by mapping private IP addresses to public ones before transmitting any data to another network.

What is the primary purpose of NAT?

The primary purpose of NAT is to translate a given set of IP addresses to another set of IP addresses. However, the reason it was originally created was to preserve the limited amount of IPv4 public IP addresses in use.

When IPv4 addresses first became the standard, the Internet required far fewer IP addresses than it does now. Though the system contains over four billion unique addresses, not all could be assigned to devices for communication. Therefore, a set of available IP addresses was exempted for testing, broadcast, and other purposes. But because the Internet was not yet commonplace for individual use, the amount of IPv4 addresses seemed sufficient.

A breakdown of network address translation (NAT)

With the proliferation of the Internet, IPv4 addresses began to near exhaustion. To circumvent the problem, software engineers created network address translation and private IP addresses to prevent shortages of public IP addresses. Network address translation is now widely used to allow a network device, like a router, to serve as an intermediary between private computer networks and the Internet.

How does network address translation (NAT) work?

Network address translation works by permitting a single device like a router to work as an agent or intermediary between the public and private networks. With NAT put in place, a single unique IP address will represent an entire group of devices within a network.

NAT results in two different types of IPv4 addresses. They are public IPs, which are publicly registered on the Internet like, and private IPs, which are not publicly registered, like

With network address translation, when computing devices need to connect to the Internet, their private IP addresses will be translated by NAT to a single public IP address.

Though network address translation may not be needed in the future with the rise of IPv6 addresses, it's still a crucial part of networks as they exist now.

What are the benefits of introducing NAT?

Network address translation is fundamental to the way networks work. There are several benefits to its usage in network systems:

  • IP conservation. As mentioned above, the primary benefit of NAT is preserving IPv4 addresses. Network address translation allows the privatization of intranets to preserve IP address space. With NAT, devices on a network need only one IP, ultimately preventing the Internet from running out of available IPs.
  • Security and privacy. Network address translation serves as the first means of defense on a network by transferring packets of data from public IPs to private IPs. The NAT router makes sure the data gets to the right place in a safe, secured manner. Within the router, NAT guards local area networks (LANs) against any suspicious or unusual traffic.
  • Peer-to-peer file sharing abilities. In some cases, network address translation techniques set up peer-to-peer connections. It helps hide internal IP addresses from external networks, which also improves privacy. Network address translation allows multiple computers to communicate responsibilities for sharing files on a network.
  • Reuse of private IP addresses. Thanks to NAT, many LANs can reuse private IP addresses. These addresses aren't used over the Internet, so they can be used without fear of address duplication.

NAT types

Three different types of NAT exist, all used to configure network address translation.

Static network address translation

In this type of network address translation, a local or private IP address receives a legally-registered public IP address assignment.

Static NAT is mainly used for web hosting. It's hardly used in organizations because of the high number of devices needing Internet service and access, which requires an IP address. For example, a business owning 500 devices would need to purchase 500 legally registered IP addresses, which would be both unnecessary and costly.

Dynamic network address translation

Dynamic network address translation maps a private IP address with a public address from a class of public IPv4 addresses. Unlike the constant mapping done in static NAT, dynamic NAT allows automatic mapping inside global and local IP addresses. It doesn't save addresses since it's a one-to-one mapping of addresses.

Port address translation (PAT)

Also known as NAT overload, PAT is by far the most popular version of NAT, typically used within homes. PAT assigns a single public IP address to a group of computers on a network. Port numbers help distinguish which traffic belongs to which IP address. PAT uses both IP addresses and port numbers.

PAT works well for many organizations as it's cost-effective. Hundreds of users can surf online on the internet with just one public IP address.

Advantages of NAT

  • IP address conservation. NAT conserves legally registered public IP addresses, thus preventing their depletion.
  • Security. Network address translation adds a layer of security as you access the Internet. It conceals your IP address and blocks malicious traffic.
  • Flexibility. Network address translation provides a flexible network system by implementing load-balancing and backup tools across the networks.
  • Cost-effective. Many homes and organizations use NAT with their legally unregistered IP addresses. They don't have to invest in new IP addresses for their devices to access the Internet.
  • Simplicity. It eliminates address renumbering in the event a network evolves or changes.
  • Speed. NAT is more transparent to both source and destination devices than VPNs and proxy servers, which results in quicker speeds.

Disadvantages of NAT

  • IP traceability. Path delays in IPv4 communication resulting from network address translation configuration can affect performance and end-device IP traceability in the long run.
  • Usage of protocols. Though most devices work with NAT, not all apps and technologies work perfectly with a NAT-configured network.
  • Memory usage. Network address translation involves a myriad of technicalities. The technology profusely consumes memory resources and plenty of processor space to translate IPv4 addresses. It must retain the data from translation as well.
  • Troubleshooting issues. There's a risk of troubleshooting and compatibility issues, primarily in remote locations. 

NAT application in video games

In addition to being part of a network, NAT has become a part of many videogame systems. It describes the state of networks, which is useful for gaming. However, each console uses network address translation in a different way.

Microsoft's Xbox system named their network address types Open, Moderate, and Strict. With the Open NAT type, the Xbox is able to communicate and receive requests. As a result, other players can join and play games. It also allows users to communicate with video or audio and host lobbies.

Moderate NAT type allows for players to connect, but not host; game lag is more likely and games are slower. NAT type Strict only allows users to connect with Open players, and it runs the risk of disconnection mid-game.

The PlayStation system also offers three network address translation types to users, though they identify them differently. PlayStation's NAT Type 1 provides a clear gaming experience as it transfers unrestricted data between all the devices within a given network. NAT Type 2 provides Internet access behind the router for players, and NAT Type 3 is least preferable, as it struggles to provide stable connections in most cases.

Frequently asked questions

Does NAT affect Internet speed?

Yes; NAT slows down your Internet speed. Network address translation configuration takes more time, which affects overall Internet connections. However, with a reasonable router, the difference is not noticeable.

What is the difference between NAT and PAT?

Both translate IP addresses from private to public and vice versa. The biggest difference is that PAT makes use of port numbers to map IP addresses while network address translation doesn't.

What's the difference between public and private IP addresses?

Public IP addresses are publicly registered on the internet, while private IP addresses aren't publicly registered.

What is double NAT?

In double NAT, more than one network device (specifically a router) in a private network performs network address translation.

What is NATing?

NATing is a colloquial term that refers to the process of performing network address translation.