What Is a NAT Firewall on a VPN? The Complete Guide

NAT firewalls protect private networks by using routers as firewalls. It only allows internet traffic if a device on the private network requests it. Furthermore, it prevents communication with potentially malicious Internet devices by discarding unwanted requests and data packets.

NAT stands for Network Address Translation, which rewrites the headers of data packets so they can be routed between networks correctly. The NAT firewall safeguards a network’s identity and does not display internal network IP addresses to the Internet.

NAT firewalls on VPNs don’t need any additional configuration since it come integrated with the servers. However, ensure that your VPN provider supports NAT firewalls and has this feature. You can turn on or off NAT firewalls in your VPN app settings or purchase them as an upgrade.

VPNs that use NAT firewalls provide users with unique private IP addresses, extending all the benefits of NAT firewalls to your VPN connection. Let’s look deeper at what a NAT firewall is and how it operates to provide the ultimate network security.

How Does NAT Firewall Work?

NAt (Network Address Translation) operates on a network router by converting IP addresses to public IP addresses. The main purpose of a NAT firewall is to prevent unauthorized access and potential threats on a network. 

Source: FS Community

NAT firewall ensures that only the verified and requested traffic can pass through the between networks. Thus, it protects the devices from contacting spammy or risky devices on the network. Moreover, it protects a network’s identity by not exposing the internal public IP address to the Internet.

Summary: NAT firewalls translate individual device IP addresses for communication with the Internet into a single public IP address. It shields individual device addresses and prevents unauthorized traffic to a network.

Types of NAT Firewalls

Several types of NAT firewall comes with their advantages and disadvantages. Here are some examples of different types of NATs.

• Static NAT: Static NAT refers to a one-to-one firewall known as balanced NAT. In other words, there should be an equal number of IP addresses to translate local and outside networks. It is commonly used when a private network device needs to be accessible from the Internet via a public IP address.
  

• Dynamic NAT: It uses a pool of public IP addresses for mapping private IP addresses to public IP addresses, unlike Static NAT. Multiple personal IP addresses are dynamically mapped to a pool of public IP addresses this way. It’s more efficient to use Dynamic NAT because public IPs are expensive.
  
• Overloading NAT: Overloading NAT, also called Port Address Translation, is a way of sharing a single IP address on a private network. It operates by using different port numbers to differentiate between the devices. It’s commonly used on home networks like Wi-Fi where multiple devices use the same IP address.

Summary: Static NAT provides a fixed mapping for specific devices, while dynamic NAT and PAT allow for more flexible use of IP addresses and port numbers. 

Which NAT type is Best?

Open NAT, known as Type 1, is the fastest and best NAT protocol among all NAT types. It enables unrestricted and seamless communication between devices on the network without affecting the speed or ping. OpenNAT offers speed, security, and connectivity making it an ideal NAT for online gaming.

Does NAT Affect Internet Speed?

In short, no. It’s a common myth that people think NAT firewalls affect internet speed. However, you should ensure you’re using the correct type of NAT for your work or entertainment. As an example, NAT type 3 is bad for gaming, but switching to a moderate NAT type 1, as mentioned earlier, can significantly improve gaming speed.

What are the Advantages of a NAT Firewall?

Basically, the main benefits of a NAT firewall include protection against cyber attacks, preventing IP address leaks, and enhancing privacy and security. There are some benefits of using a NAT firewall on your network are given below:

• Network Security: NAT provides a baseline level of security by concealing the IP addresses of the internal network from external networks. This makes it more difficult for hackers to find and attack each device on the network.
  
• Monitoring: NAT monitors network traffic. It allows or blocks certain types of traffic, providing administrators with more control over the security of the network.
  
• Realtime Privacy: NAT converts private IP addresses to public IP addresses, protecting the privacy and security of data on the devices and networks.
  
• Data Retention: NAT discards unauthorized internet traffic without a private IP address outside the gateway, reducing the number of hacker attacks.
  
• Simplified Network Management: NAT simplifies network management by using the private IP addresses on the internal network. This allows the network to easily accommodate new devices without affecting the internet connectivity.
  
• Load Balancing: NAT allows multiple devices on the private network to use the same public IP address, helping to balance network traffic and increase performance.
  
• Hardware Firewall Solution: NAT works like a hardware firewall, although it is not a firewall or security tool by design. It protects your devices from the pesky threats of the network and the Internet.

What are the Disadvantages of a NAT Firewall?

While NAT firewalls have many benefits, they also have some drawbacks that need to be addressed. For example, it might consume more processing power and slow down your network, causing switching delays, especially when working with realtime applications like VoIP or video conferencing.

It can also make it hard to use specific applications and protocols, like online games and P2P file sharing since it needs to be able to communicate directly between devices. On top of that, NAT can be complicated to manage in more extensive networks, leading to more administrative overhead and more mistakes.

Lastly, while NAT can provide some basic security, it could be a more complete security solution and can be easily hacked by sophisticated attackers.

Summary: NAT firewalls have many benefits but can also cause delays in switching, consume more processing power, and affect online gaming and P2P file sharing.

How to Enable NAT Firewall on VPN?

You may ask yourself, should I enable the NAT firewall? Ensure that your VPN service comes with the NAT firewall feature. If the feature is available, you can enable or disable it from the VPN settings. Some VPNs offer NAT firewalls as a built-in feature to protect you from dangerous cyberattacks like Man-in-the-middle attacks.

FAQs

Is NAT TCP or UDP?

No, NAT is not limited to TCP or UDP. But the way it works can be different from one protocol to another. NAT works great for TCP connections but can be tricky for UDP connections since UDP is a connectionless protocol.Learn the difference between TCP and UDP protocols. One is good for secure data transmission another is good for speed and low latency.

What OSI level is NAT?

NAT works at Layer 3 (OSI model) because it changes the IP header and is responsible for converting private IP addresses to public IP addresses and vice-versa. When a packet enters an interface, NAT takes precedence over firewall rules.

How is NAT different from a firewall?

By default, NAT provides some level of security, but it cannot replace a firewall. A firewall monitors and controls network traffic based on predefined security rules and can defend against a wide variety of threats.

Conclusion

To sum up, a NAT firewall protects private network connections to the Internet by using routers as barriers. It allows internet traffic only when requests are made from devices inside the private network, blocking unwanted or potentially harmful traffic from the Internet. Moreover, it masks internal IP addresses to protect a network’s identity.