Stateful vs. Stateless Firewalls: What's the Difference?

Stateful firewalls are capable of monitoring and detecting states of all traffic on a network to track and defend based on traffic patterns and flows. Stateless firewalls, however, only focus on individual packets, using preset rules to filter traffic.

Firewalls provide critical protection for business systems and information. Operating according to prewritten security rules, firewalls are applications that monitor and manage the traffic flowing into and out of your network. Understanding the differences between stateful vs. stateless firewall technology helps ensure your business is protected appropriately.

Aren't All Firewalls the Same?

No, there are many types of firewalls. Incoming and outgoing traffic abides by various rules set within an organization's firewall. Likewise, different types of firewalls exist to ensure a best fit for a company's network and needs. In either case, these network security measures are designed to keep untrusted, corrupt files out while protecting the company's network assets.

Firewall types tend to be either network firewalls running on network hardware or host-based firewalls that rely on host computers to oversee traffic. When researching firewall types for your business, you may have discovered stateful and stateless firewalls. There is also a third firewall type — next-generation firewalls — which has become the most recommended type. Let’s take a closer look at each.

What is a Stateful Firewall?

Stateful firewalls monitor all aspects of the traffic streams, their characteristics and communication channels. These firewalls can integrate encryption or tunnels, identify TCP connection stages, packet state and other key status updates.

What is a Stateless Firewall?

Stateful firewalls monitor all aspects of the traffic streams, their characteristics and communication channels. These firewalls can integrate encryption or tunnels, identify TCP connection stages, packet state and other key status updates.

Pros and Cons of Stateful vs. Stateless Firewalls

As with most compare and contrast scenarios, stateful and stateless firewalls each have their own strengths and weaknesses. Here are the pros and cons of stateless firewall vs. stateful firewall options.

Pros of Stateful Firewall

• Stateful firewalls are highly skilled at detecting unauthorized attempts or forged messaging.
• The powerful memory retains key attributes of network connections.
• These firewalls do not need many ports open for proper communication.
• Stateful firewalls offer extensive logging capabilities and robust attack prevention.
• An intelligent system, stateful firewalls base future filtering decisions on the cumulative sum of past and present findings.

Cons of Stateful Firewall

• Vulnerabilities may allow a hacker to compromise and take control over a firewall that is not updated with the latest software releases.
• Some stateful firewalls can be tricked to allow or even attract outside connections with an action as simple as viewing a webpage.
• Man-in-the-middle attacks may pose greater vulnerabilities.

Pros of Stateless Firewalls

• Stateless firewalls deliver fast performance.
• Heavy traffic is no match for stateless firewalls, which perform well under pressure without getting caught up in the details.
• Stateless firewalls have historically been cheaper to purchase, although these days stateful firewalls have significantly come down in price.

Cons of Stateless Firewalls

• Stateless firewalls do not inspect traffic.
• The stateless firewall also does not examine an entire packet, but instead decides whether the packet satisfies existing security rules.
• These firewalls require some configuration to arrive at a suitable level of protection.