Stateful vs. Stateless Firewall

Stateful vs. Stateless Firewall – What’s the difference?

5 Mins Read

CybersecurityStateful vs. Stateless Firewall – What’s the difference?

Stateful vs. Stateless

As businesses across every industry become more reliant on data, intellectual property, and digital banking, there is more to lose from hacking attacks than ever before. With the increasing cybersecurity needs, businesses are shifting to the most sophisticated security features possible. 

An important part of keeping safe in such times are firewalls. Firewalls evaluate each data packet that attempts to enter a computer system. They help businesses detect unsafe traffic before it enters and causes malicious behavior. 

While incredibly important, they are also a little confusing due to the different variety and types. The two important categories are Stateless and Stateful Firewalls. 

Both are equally helpful but come with their pros and cons. Read on to learn about their difference, importance, and suitability under different individual and business situations. 

What is Stateful Firewall

What is a Stateful Firewall?

Stateful Firewalls consider the state of connection of each data packet, the content inside it, and the behavior of each data. 

Along with this, it also evaluates the channels of communication to assess if it is conducting any suspicious activity. In Stateful Firewalls, it is all about being rigorous and tracking data at different points in time. 

It is also data-intensive compared to Stateless Firewalls. This means it records every activity that a specific data packet conducts when connected with the system. 

By continually logging the behavior this way, it is more capable of decoding any hard-to-find suspicious activity. Where Stateless Firewalls focus on one-time entry permission, Stateful Firewalls monitor activity even after the packet has entered the system. 

In simpler terms, Stateful firewalls are all about the context— the surrounding situation, other peripheral data, metadata inside, the connection stage, the endpoint, and the destination. It goes beyond the standard/maximum evaluations that stateless firewalls complete. 

One prominent feature of such firewalls is the ability to make decisions independently, even without administrator input. 

For example, suppose the administrator has set permission parameters based on a certain IP address, TCP connection, and other header information, and the data packet satisfies the permission standards. 

In that case, the Stateful Firewall can still reject permission if it detects other suspicious activity or a malicious entity within the packet. 

After approval, the data packets are added to a dedicated database known as the state table. It includes information on all the data packets that have been approved for entry, making future permissibility easier. 

A common example of a Stateful Firewall is the Microsoft Defender Firewall, the standard Firewall on Windows Operating Systems.

What are the advantages of using Stateful Firewalls?

Stateful Firewalls look throughout the data packet rather than just the surface information, making it less vulnerable to malicious attacks. 

It keeps a record of previous activity, helping the system build more and more information about different packet activities to detect subtle malicious activity. It also helps to prevent future attacks by learning through past experiences. 

What are the disadvantages of using Stateful Firewalls?

They are highly data-driven and need more storage and memory capacity. They may be an overkill for individual and small business needs. 

Unless the system is powerful enough, Stateful Firewalls come with a lot of lag as they need to process more information beyond the surface data. While they are more rigorous and defensive, they are highly vulnerable to a specific type of intrusion attack. 

Man-in-the-middle (MITM) attacks are a common way to get inside a system by intercepting the connection between two parties. Due to the data records, MITM attacks become easier to deploy as a hacker can spy and change the traffic information on the system. 

What is a Stateless Firewall

What is a Stateless Firewall?

 As the name suggests, Stateless Firewalls don’t consider the state of connection and other peripheral information. They use a straightforward standard to allow or deny access to different data packets entering the system. 

In most cases, they only evaluate the header information on each packet— source, endpoint, IP destination, and current connection stage. If any data packet doesn’t satisfy the permission parameters, it is denied access. 

These parameters can be purposefully set by the administrator and pinpointed to the user’s exact preferences. This means the permission conditions can be made as narrow or broad as needed by the user. 

One prominent feature is the use of the stateless protocol. The protocol forces the firewall to evaluate every data packet in isolation— regardless of any previous activity, connection, or behavior of the data. It also skips the deeper layer of data embedded within the packet, which may be carrying a threat or malware. 

A common example of such a firewall is the Extended Access Control Lists on Cisco Routers. 

What are the advantages of using Stateless Firewalls?

While there is no doubt that Stateful Firewalls are more comprehensive in their approach, most businesses still prefer them.. This is because of its quick response and real-time evaluation. 

Stateless Firewalls are much faster and can allow new connections to be established almost instantly. This makes them more appropriate for systems that deal with a lot of traffic. 

Even though they aren’t as robust, they satisfy most individual and business basic and advanced security needs. They are also highly personalizable as the permission parameters are decided and easily updated by the administrator. 

Moreover, the increased risk of MITM attacks is also minimized as Stateless Firewalls don’t record any data. Their storage and memory needs are also minimal and don’t require high financial resources and infrastructure to run.

What are the disadvantages of using Stateless Firewalls?

Stateless Firewalls ignore the context and the metadata. This can make it easier for hackers to sneak in malware while packaging it as safe traffic. 

For this reason, businesses with high-security needs such as those handling banking details, valuable IP, important data, or other company workflows may not find stateless firewalls helpful. 

Even the firewalls designed for individual use in simple computers are Stateful Firewalls— for better security. Unless you have high cost-saving needs, the Stateless Firewall may bring more harm than benefit in the long run. 

Which firewall is suitable for your needs?

Since both Stateless and Stateful Firewalls come with their own set of advantages and disadvantages, picking the right one can be confusing. It is all about finding the right balance between the initial costs and the long-term needs of your business. 

You should choose Stateful Firewalls if your business:

  • Handles a lot of new, unfamiliar traffic from different sources.
  • Has valuable intellectual property, workflow, and other data stored on the system.
  • Doesn’t have a limited budget for advanced cybersecurity management.
  • Will lose more in case of an attack than what it costs to use a stateless firewall. 

You should go with a Stateless Firewall if your business:

  • Rarely connected with unfamiliar traffic.
  • Handles a lot of traffic throughout the day.
  • Doesn’t have extensive system resources, including memory and storage.
  • Already has other compensatory security features such as a next-gen antivirus software. 


When it comes to firewalls, no one type is better than the other. What works for a different business may not be enough for yours. Make sure to carefully evaluate all the ins and outs of your security needs, and conduct a cost-benefit analysis. 

Sometimes, a Stateful Firewall may be an overkill for your minimal security needs. On the other hand, some businesses have a lot to lose if a dangerous data packet gains access to their systems. 

Sameed Ajax Sameed is a Digital Content Producer at PureVPN who covers cybersecurity, streaming, and weekly news. Besides that, he wastes time playing FIFA, eating pizza, and sending tweets.

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