What Is Network Address Translation? (Types And FAQs)

Updated 30 September 2022

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Network address translation (NAT) improves network communication security and reduces the requirement of a number of unique internet protocols (IP) for an organisation. This technique helps map multiple local IP addresses to one single IP to allow efficient communication over a network. By acquiring a fundamental understanding of NAT and how they work, you can help ensure a secure network for an organisation and learn one of the important skills for a successful networking career.

In this article, we answer the question, "What is network address translation?", discuss how it works and its importance, outline its different types and levels and answer some frequently asked questions about networking protocols and how they affect your internet access and security.

What Is Network Address Translation?

Knowing the answer to the question, "What is network address translation?" can help you find how it transforms a device's internal address on a private network into a public address that can connect to the internet. NAT protocol can help add extra protection for devices connected across the network, and a router or firewall can incorporate it. When connected via the NAT protocol, a NAT connection can be static (in which case one device maintains the same public internet protocol (IP) address) or dynamic (in which case the device gets a public address from a pool of available addresses.)

What Is The Importance Of Network Address Translation?

A unique IP address is necessary for a networking system to communicate with the internet. A user can communicate with a network device by using its 32-bit identification and location. Although the internet protocol version 4 (IPv4) addressing system made billions of these unique addresses available over the previous few decades, you can not assign all of them to devices for communication. Multiple series for IPV4 is not usable as they are available only for special use such as broadcasting, testing and specific designated military reasons.

There are almost 5 billion IPv4 addresses available for communication. The number of usable addresses is almost exhausted because of the rapid growth in the number of devices connected to the internet. The IPv6 protocol addresses the problem by adding 340 trillion trillion trillion IP addresses, but it is difficult to move all existing devices from IPv4 to IPv6. NAT protocol helps conserve IP addresses by allowing private IP networks to utilise unregistered IP addresses to connect to the internet. NAT converts private internal IP addresses into globally unique addresses before forwarding packets between the networks it connects.

How Does Network Address Translation Work?

The internal network and the external network are the two local networks that a NAT chooses as its gateways. Often, IP addresses of devices on the internal network can not route to outside networks. The gateway has a few externally valid IP addresses assigned to it. The gateway simulates outbound traffic from an internal system as coming from one of the legitimate external addresses. It redirects incoming traffic intended for a valid public IP address to the relevant internal device. This helps promote security.

The network address translation process helps to validate or authenticate incoming data packets and matches them to outgoing requests. By reducing the number of globally valid IP addresses a business requires, NAT has significantly contributed to extending the usable life of IPv4.

Types Of Network Address Translation (NAT)

Following are the three major types of NAT protocol:

Static NAT: This NAT selects the same address when the local address gets updated to a public one. This ensures that the router or NAT device always has a fixed public IP address.
Dynamic NAT: This NAT cycles through a pool of available public IP addresses rather than selecting the same IP address each time. As a result, every time the router converts a local address to a public address, the router or NAT device receives a new address.
PAT: Port address translation (PAT) protocol enables several devices on a single private network to connect to the internet using the same public IP address. A port number follows the IP address of data transmitted and received over a PAT connection.

Different Levels Of NAT Connections

A routing device may assign a connection to one of three levels when establishing a NAT connection. Although they are still not connections, all three levels can interact with other global connections via the internet. When selecting a network protocol, it is important to understand the following three levels of NAT connections:

Open NAT

This is an ideal and most common NAT connection type. Any of the three NAT connection types can help connect devices to the internet and it can communicate with those devices. It can also host a call or connection itself or join one that is being hosted by another user.

Moderate NAT

When connected to the networking protocol, the moderate NAT connection monitors and limits specific functions for users from the outside world. A user with a moderate NAT connection can join and communicate with some users, but it may prevent them from doing the same with other users. Although a moderate connection can act as a host, it happens more often than a moderate NAT connection connects to an open NAT connection host.

Strict NAT

The most severe limitations on network connection capability are present with strict NAT connections. Connecting with users who use either strict or moderate NAT protocols may not be possible while using a strict NAT protocol to access the internet. Such a device can only connect to other open NAT devices on that connection and you can only establish connections by connecting to an open NAT host.

Frequently Asked Questions About NAT Connections

There are many similarities and a few key differences between the various network protocols. Here is a list of frequently asked questions about network protocols and how they work:

What are the benefits of a static NAT protocol?

A static NAT protocol is suitable when a device needs a fixed IP address so that other devices may access it through the internet. This is crucial for servers and other devices because it enables constant access to that IP even if the device disconnects from the network and needs to reconnect. This is helpful in cases like gaming servers, where many users from different parts of the world continually connect to the same server. It is also useful when setting up a service where you may require a reliable connection address, such as email forwarding.

What are the benefits of a dynamic NAT protocol, such as PAT?

When trying to reduce the number of public IP addresses required for multiple connections, a dynamic NAT connection, such as a PAT connection, is helpful. PAT connections greatly reduce the requirement of public IP addresses since you can hook several devices to the same public IP address via ports. This makes it a more effective way of connecting to the internet for devices that do not require a static IP address.

Using a dynamic protocol like PAT to connect to a network also adds an extra layer of security. The device's private address is invisible to the public by being translated into a port number during the PAT protocol. This may make it more challenging for unauthorised users to access a device using a PAT connection via the internet.

How does NAT work in a router?

The NAT router searches the routing database for the destination address. The NAT router interprets the packet and records the action in the address translation table if it has an entry for that address. If the target address is not in the routing table, the NAT router rejects the packet.

What is the best connection type for a business installation?

Most commercial buildings use dynamic NAT technology, such as PAT protocols. This makes it possible for all devices in a building or a department to access the internet using the same IP address. With a PAT protocol, each device gets a separate port to enable a distinctive connection without the requirement to reserve a large number of public IP addresses to represent each device on the network.

When installing permanent servers, a business may benefit from using a static NAT connection or a static PAT connection. When setting up forwarding services or other types of connectivity to access data on the company's server also, you may require a fixed IP address.