Fundamentals of NAT and how it reshapes the internet

Anton P. | June 16, 2020

The Network Address Translation (NAT) is a solution to the ever-growing number of internet-connected devices. Creators of IPv4 believed that 4.5 billion IP addresses are a sufficient number. However, with new devices connecting to the internet daily, IPv4 technology is no longer enough to meet the demand. Hence, NAT emerged as the standard for reusing IP addresses and guaranteeing smoother digital space. In this article, we will try to squeeze in all the concepts you should know about.

What is NAT exactly?

As mentioned, NAT stands for Network Address Translation. It is the technology behind the conservation and reuse of IP addresses. Your internet-connected router gets a single public IP address. However, the devices that connect to the router receive private IP addresses. These are not fit to connect to external web servers. Hence, NAT is a necessary component, driving the web traffic from your router to the specified web server.

In the tech world, the IPv4 address exhaustion refers to the depletion of IPv4 protocol, and the introduction of IPv6. Currently, both of these protocols co-exist and attempt to resolve the innate issues with the internet infrastructure. Since the full integration of IPv6 protocol will take some time, NAT is the option for reducing occupied public IP addresses.

This technology can work on the firewall, computer, or router. For instance, let’s say that you set up a NAT router. Instead of assigning individual IP addresses to all internet-connected devices, NAT makes them share the same one. While NAT is a solution to the shortcomings of IP addresses, it does have its drawbacks. For instance, it can introduce some major issues by violating standard protocols and applications.

What is a NAT firewall?

NAT firewall moderates the traffic that travels through the gateway. In some cases, it can prevent the traffic from reaching your device if deemed suspicious or unsolicited. Long story short, it is a mediator that manages all your incoming and outgoing requests.

Traditionally, when users visit websites, their devices transfer a request to the router, which then sends it to the website’s server. If the server approves the request, the user will receive the site. During this process, a firewall restricts communication in case of potential threats or unsolicited requests. In the case of NAT firewall, it permits the requests initiated by the devices of a specific private network. It discards potentially dangerous requests, preventing the communication that might be dangerous. However, experts from Stanford University indicate that the NAT security does not function as a regular firewall. Its analysis is of the surface level, meaning that it won’t deal with more deceptive and camouflaged threats.

Principles of how NAT works

In the simplest terms, it is the technology that operates as the mediator between the internet (or public network) and a local network (or private network). As a result, one IP address represents all of the devices connected to the router. It is essential for corporate networks. All internet-connected hardware owned by companies can function with the same address. To get into more detail on how this IP-saving method works, here are several stages of this process:

  1. Before establishing the main principles, you should be able to differentiate between two types of addresses. Inside local address refers to your private IP address, indicating your location and internet service provider (ISP). When you connect to websites, their IP addresses are outside local addresses.
  2. Your device (computer, smartphone, etc.) transfers requests to a web server in the form of packets. There can be various types of information within them: recipient’s and sender’s IP address, port numbers, etc.
  3. The data packets reach the appropriate web server.
  4. The requested information reaches the router. At this moment, NAT steps in to either accept or reject the incoming request.
  5. Then, the NAT replaces the data packet’s public IP to the original private one and reroutes the request back to the device.

Can you use both NAT and a VPN?

NAT can detect and prevent potentially dangerous connections. However, its protection is not enough in the current landscape of digital privacy issues. Hence, it is optimal to use a VPN to safeguard your online activities even more. The nature of these applications might prevent them from peacefully co-existing in your device.

A VPN encrypts all your traffic. The objective of NAT is to investigate the incoming and outgoing traffic to determine its authenticity. So, some no longer prevalent encryption protocols such as PPTP or IPSec can be an obstacle. Luckily, most of the VPN providers address this issue by incorporating the so-called passthroughs. Even when providers omit such additional overlays, the VPN should function as normal due to more advanced encryption protocols applied. Atlas VPN combines the protection of AES-256 and IKEv2 protocol to offer the most advanced encryption. The NAT technology should not malfunction when used in conjunction with these protocols.

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