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What is Network Address Translation (NAT)?

What is Network Address Translation (NAT)? – NAT is a feature that most people do not know but always use. In ADSL modems or Router devices such as Cisco, NAT (Network Address Translation) is built in by default.

What is Network Address Translation (NAT)?

What is Network Address Translation (NAT)?

You must have heard the IPv4 protocol. Today, the IPv4 protocol for Global IP addresses is almost exhausted. If NAT did not exist, only certain people or firms would access the Internet today.

The Global IP addresses provided by the ISP are divided into two. These; Dynamic IP and Static IP addresses.

The dynamic IP addresses provided by the ISP work as DHCP, and when you close and reopen your ADSL modem, the network device will get a new IP address. Static IP addresses provide only one Global IP address for a specific fee.

These IP addresses used on the Internet are allocated by ICANN. Millions of people spend every day on the Internet. Do you think that IPv4 IP addresses will be sufficient in the future when the number of people increases? Of course not!

The NAT service has been developed to use IPv4 addresses more efficiently. A person or organization with a single Global IP address can distribute all clients on the local network to the Internet with a single Global IP address using Network Address Translation.

What Does NAT Do?

Basically, NAT (Network Address Translation) is usually configured to connect two networks together. However, NAT is used to hide internal network IP addresses. In short, NAT converts private IP addresses in the network to a single Global IP address and passes packets to the target network. Therefore, NAT provides internal network security.

There are private IP addresses reserved for the local network. You can configure these IP addresses for all clients on the internal network. Depending on the nature of your network, you can also create a CIDR configuration.

Reserve IP addresses are as follows;

192.168.0.0 - 192.168.255.255 (65,536 IP addresses)
172.16.0.0 - 172.31.255.255 (1,048,576 IP addresses)
10.0.0.0 - 10.255.255.255 (16,777,216 IP addresses)

When using these private IP addresses on the local network, for example, a computer with an IP address of 192.168.1.100 is subjected to NAT to access the Internet.

As an example of everyday life, the ADSL modem you use in your home has a Network Address Translation feature. To check the NAT feature on your ADSL modem, first, write the management IP address of your device to a web browser and press Enter. After accessing the management panel of your device, you can review the NAT feature in the WAN section.

Active NAT Service over ADSL Modem;

What is Network Address Translation (NAT)?

What are NAT Advantages?

The advantages of NAT (Network Address Translation) are;

  • The main advantage of NAT is that it can prevent the depletion of IPv4 addresses.
  • Provides an additional layer of security by hiding the source and destination IP addresses.
  • It provides more flexibility when connecting to the Internet.
  • It allows to use your own private IPv4 addressing system and prevent the internal address changes if you change the service provider.

What are NAT Disadvantages?

  • It overloads your device’s RAM and Processor because it keeps NAT’s inbound and outbound IPv4 addresses in memory.
  • It may cause a delay in IPv4 communication.
  • NAT also causes loss of traceability of the IP address between the target and the source device.
  • Some technologies and network applications may not work as expected on the NAT structured network.

What are NAT Types?

Network Address Translation is divided into 3 according to the intended use. These;

Basic NAT

Basic Network Address Translation only performs address translation using a single generic IP address and does not use port mapping.

Dynamic NAT

Dynamic Network Address Translation, unlike Basic NAT, the IP addresses purchased by the ISP are collected in a single NAT pool on the network device. As a result, when a client on the network tries to access the Internet, the public IP address that is empty in the pool will be used.

Port Address Translation (PAT)

PAT is used to connect all computers on the LAN internally with a single public IP address. PAT uses a value between 1024 and 65535 for the local port number.

How PAT Works?

In a PAT, the router checks the NAT table when a computer in the LAN wants to connect to the HTTP server. If it cannot find a record of the IP address, it writes the IP address + port number of the computer to the NAT table. The router then translates this computer to the Public IP address and sends the packet.

The Destination Router receives the IP packet sent and sends the packet to the destination computer on the internal network. However, the destination router cannot identify the local network address from the incoming IP packet.

How Network Address Translation Works? ⇒ Video

For a better understanding of what Network Address Translation is, you can watch the tutorial video configured in Packet Tracer and also subscribe to our YouTube channel to support us…

   Final Word

In this article, we have discussed what is NAT (Network Address Translation) that helps prevent the depletion of IP Version 4 addresses, and we have briefly talked about how it works. Finally, we have explained the types of Network Address Translation, and we mentioned what do they do. Thanks for following us!

If this article is helpful, please send us feedback by commenting. Thanks in advance, take care of yourself!

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