Network Address Translation (NAT)


What is NAT, and how does it work?

The process of translating one or more local IP addresses into global IP addresses and vice versa to offer Internet connectivity to local hosts is known as Network Address Translation (NAT). A router or firewall is used to implement NAT. Read on to learn more about NAT.

One public IP address is required to connect to the Internet; however, you can use a private IP address in the private network. NAT allows numerous devices to connect to the Internet using a single public address.

To accomplish this, a private IP address must be converted to a public IP address. The process of translating one or more local IP addresses into one or more global IP addresses and vice versa to offer Internet connectivity to local hosts is known as Network Address Translation (NAT). It also performs port number translation, masking the host’s port number with a different port number in the packet that will be transmitted to the destination. It then creates entries in the NAT table for the relevant IP address and port number. A router or firewall is used to implement NAT.

Essentially, NAT permits a single device, like a switch, to go about as an agent between the Internet and a nearby network. That implies that a primary, solitary novel IP address is expected to address many PCs to anything outside their network.

What is Network Address Translation (NAT)?

Network Address Translation (NAT) allows private IP networks with unregistered IP addresses to connect to the Internet, conserving IP addresses. NAT changes private internal network addresses into legitimate, global exceptional addresses before sending packets between the networks it links.

Network address translator settings can reveal only one IP address for a whole network to the outside world, masking the entire internal network and adding security. Network address translation is commonly used in remote-access scenarios because it provides both address conservation and increased security.

How does Network Address Translation work?

A NAT router selects gateways between two local networks: the internal and external networks. IP addresses assigned to systems on the internal network are often not routable to external networks.

The gateway is given a couple of externally valid IP addresses. Outbound communication from an internal system is disguised as traveling from one of the substantial outer addresses using the gateway. It redirects incoming traffic to the proper internal system when directed to a legitimate external address.

This contributes to safety since each outgoing or incoming request should pass through a translation process, which allows for the qualification or authentication of incoming streams and the matching of outgoing requests.

The different NAT Types

There are three types of NAT. We’ll go through each of them in detail in this section.

1. Static NAT

Static NAT is a sole unregistered IP address mapped to a legal Public IP address. A one-to-one mapping is created within local and global addresses, which is commonly used for web hosting. However, they are ineffective in businesses since many people utilize the Internet and require access to it, which necessitates the usage of a public IP address. For example, if a firm needs an internet connection for 2000 servers, it must purchase 2000 public addresses, which is costly.

2. Dynamic NAT

The differences between dynamic and static NAT are minor. The basic idea is that the provider assigns multiple external IP addresses distributed by the router based on demand. While static network address translation maintains the continuous mapping between local and global addresses, dynamic NAT lets you map inside all the addresses. Dynamic NAT allocates public addresses from a pool.

3. Port NAT

PAT is just like dynamic NAT, in which many private addresses are mapped to a single public IP address. When the number of clients outnumbers the pool of global addresses, this method is employed. You can save a lot of address space by using PAT. The ISP gives the router a single IP address, but it can be used by multiple family members simultaneously. The PAT keeps the address in the address pool, permitting the switch to involve one internal address for some local address. At the end of the day, a solitary open IPv4 address can be utilized for hundreds or even many local IPv4 addresses.

What NAT type is best?

When a device must be accessed from outside the network, static NAT is beneficial. This method isn’t often used because it wastes time registering IP addresses and produces an IP address that isn’t shared with anyone else.

Dynamic NAT has two principal use cases. The first is to take into account protocol which makes an optional, unique network back to the client. The second is assuming that you really want Bidirectional planning of Private IPs to Public IPs; however, you couldn’t care less about the unequivocal mapping among them.

PAT is a form of Network Address Translation that is very prevalent. PAT should be used if all hosts must access the Internet simultaneously. Using this strategy, a single public IP address is enough to connect thousands of hosts to the Internet.

Advantages of NAT

  • By establishing several source pools, load-balancing pools, and backup pools, NAT improves the dependability and flexibility of connectivity to the global network.
  • NAT is a well-known method of network addressing. If a global IP address is being used, address space should be correctly assigned because a network’s development may necessitate a large number of IP addresses.
  • NAT gives an additional layer of safety to the network in light of the fact that the host inbuilt in the NAT network is inaccessible by other network gadgets according to client inclination.


NAT is a critical component of firewall security. It reduces the number of public addresses used within a company and enables more stringent access control on the two sides of the firewall.

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