The 6 Tradeoffs Between a Stateful vs Stateless Firewall

Stateful firewalls track the state of network connections. This is not the case with stateless firewalls. Although the difference between stateful and stateless firewalls is relatively simple, choosing one may not be so straightforward.

The status of a network connection refers to its status, whether the connection is being established, actively transmitting data, or is being closed.

Stateful firewalls track this context, monitoring the entire traffic flow – where packets come from, where they are going, and what type of traffic is being relayed.

Stateless firewalls ignore this context – they treat each packet as independent and have no knowledge of previous packets.

These fundamental differences make stateful firewalls suitable for some situations and stateless firewalls better for others.

When to use stateful versus stateless firewalls

Stateful firewalls are necessary in dynamic, complex environments where tracking connection status is important for security. They offer deeper inspection capabilities, which makes them ideal for networks with varying traffic or where detecting malicious activity within ongoing sessions is critical.

Ideal for static networks with predictable traffic patterns, stateless firewalls can allow or block packets based on fixed rules without the need for session tracking. These firewalls provide a low-maintenance solution for scenarios that do not require in-depth inspection of connection status, such as enforcing basic port restrictions or as a first layer of defense in high-speed environments.

There are several Different types of firewallsmay be stateless or stateful. Packet filtering firewalls are typically stateless, Web Application Firewall (WAF) Usually stateful, Firewall as a Service (FWAAS) Can be stateful or stateless.

See: five Why stateful firewalls are a must For any business.

Tradeoffs between stateful and stateless firewalls

A stateful firewall will always tell you more than a stateless firewall, but this comes at a cost. Is it better to choose a stateless firewall for speed and performance?

As you set up your firewall and protect different parts of your network, here are the main tradeoffs to consider when considering stateful versus stateless firewalls.

1. Stateful firewalls consume more resources

Because stateful firewalls inspect packets and track the status of network connections, they perform much slower than stateless firewalls. In the wrong place or performing the wrong task, stateful firewalls can really slow down your network.

Meanwhile, stateless firewalls are a faster alternative because they operate by examining the source and destination addresses of a single packet. This means they ignore connection status and therefore can parse incoming packets faster.

All in all, stateless firewalls are more suitable for high-traffic, low-risk situations. With their exceptional speed, they can quickly evaluate packets without putting a strain on network resources. When the level of security requires more intensive effort, stateful firewalls are usually worth the sacrifice in performance.

2. Stateful firewalls are less likely to trigger false positives

Stateless firewalls can put your network in a constant state of “fight or flight.” This is not common with stateful firewalls, simply due to the way they track connection status.

Stateful firewalls can and will recognize established connections, so they are more sensitive to blocking traffic rather than throwing up red flags if anything potentially suspicious arises (as stateless firewalls tend to do).

Overall, stateless firewalls are more likely to generate false positives and block legitimate traffic because they lack context.

In practice, this means that stateful firewalls tend to provide more granular control over traffic, which is useful for networks that are more complex or carry more sensitive data.

For example, financial institutions and healthcare providers may find this particularly beneficial as they often have strict security requirements.

3. Stateful firewall can apply more flexible rules

Let’s say you’re an IT administrator responsible for protecting your organization’s network security. if you Ensure firewall rules follow best practicesa stateful firewall will enable you to enforce these rules with greater precision. In other words, you get more reliable, consistent protection.

However, if your traffic is more diverse (and therefore more unpredictable), a stateful firewall may be a better choice because it allows you to apply rules at the packet level. This is especially useful when you need to let through certain traffic that may not easily conform to a predefined set of rules.

For example, if a software development company frequently works with third-party vendors, the traffic from those vendors is likely to vary significantly. By using stateful firewalls that can apply more flexible rules, they can manage different traffic patterns and Maintain network security.

4. Stateless firewalls do not track connection status

This design choice reduces the complexity of managing session data, thereby reducing firewall overhead. As a result, stateless firewalls are much lighter in terms of resource consumption—they require less processing power, memory, and storage than stateful firewalls. This makes them highly efficient in environments where speed and scalability are critical, especially when handling large volumes of traffic.

One instance where this is particularly useful is in a cloud computing environment virtual server and workloads that often increase and decrease. In this environment, stateless firewalls could theoretically be deployed to ensure that traffic to and from cloud-based resources follows a predetermined set of rules.

The lack of state tracking becomes a trade-off when considering dynamic or complex traffic scenarios. The simplicity of a stateless firewall comes at the cost of being unable to detect or block context-dependent threats, such as session hijacking or more complex attack vectors. Ultimately, there is a trade-off between efficiency and security.

5. Stateless firewalls provide less control

Although stateless firewalls can be more flexible and lightweight, they provide much less precision.

Without storing network connection state, stateless firewalls treat each packet that passes through them as a separate entity, regardless of the packets that precede or follow them.

Therefore, a stateless firewall has very limited ability to differentiate between allowed and disallowed traffic. However, with a stateful firewall, while the initial request to access a secure website is allowed through, subsequent packets will be identified as part of the same connection.

6. Stateful firewalls come at a cost

Stateful firewalls are generally considered more advanced, practical, and effective than stateless firewalls. Ultimately, they become better at tracking the status of different network connections and then making decisions based on that status.

That said, this thoroughness comes with a higher price tag. Stateful firewalls also require more powerful hardware to operate at full capacity and are more complex to deploy.

You don’t have to choose between stateful vs. stateless firewalls

Enterprises often deploy stateless and stateful firewalls as complementary layers in their operations network security architecture. It’s not one or the other.

Stateless firewalls are typically placed at the network perimeter to handle high-speed traffic filtering, blocking unwanted packets based on simple rules. Behind them, stateful firewalls provide deeper inspection and context-aware security by monitoring connection status to ensure legitimate sessions are protected.

This layered approach balances performance and security, allowing enterprises to effectively manage traffic while addressing more complex threats within the network. Learn more about Where on the network should the firewall be located? and explore Latest Internet Security Tools You can use it to keep your business data safe.