5 Reasons to Use a Stateless Firewall (+3 Key Downsides)

In networking, “state” refers to the context or session data of the current network connection. Therefore, a stateful firewall tracks the state of every connection passing through it, while a stateless firewall does not.

Although they sound less restrictive, stateless firewalls are useful for protecting home and business networks. They use ACLs (Access Control Lists) to decide what traffic is allowed through and what traffic is blocked.

Of course, not tracking the state of network connections means that a stateless firewall can’t tell you as much about your network traffic as a stateful firewall can. The benefits of stateless firewalls come with trade-offs.

Enterprises often balance these trade-offs by using both types, with stateless firewalls handling bulk traffic filtering at the perimeter and stateful firewalls providing deeper inspection behind them.

By the end of this article, you’ll know when a stateless firewall works well and when other solutions might be better.

Five reasons to use a stateless firewall

1. They are efficient

The biggest advantage of using a stateless firewall is efficiency. Because they only inspect a single packet (rather than tracking connection status like a bulky stateful firewall), stateless firewalls act like lean, mean security machines.

This makes them more useful when handling large amounts of traffic. For example, stateless firewalls don’t consume as much memory and processing power because they don’t have to keep up with the specifics of every connection that goes through.

For example, if you are running a large website that receives a lot of traffic, you won’t want a firewall to slow it down. With a stateless firewall, you can set up strong network security protection without compromising your website’s performance.

See: Avoid these Errors when setting up network security.

2. Stateless firewall is easy to set up and maintain

Setting up a stateless firewall is a piece of cake compared to a stateful firewall.

Stateful firewalls dynamically maintain state tables to track ongoing connections and ensure legal traffic by monitoring session information.

In contrast, stateless firewalls rely on a fixed set of filtering rules, such as allowing or blocking packets based on IP address, port, or protocol. This makes stateless firewalls easier to configure and less resource intensive, although it also makes them less adaptable to dynamic or context-sensitive traffic than stateful firewalls.

3. Stateless works well at network boundaries

Stateless firewalls are often used as the first line of defense for network security due to their simplicity and effectiveness in blocking unwanted traffic.

They are particularly useful in scenarios where only basic access control is required, such as filtering traffic between trusted and untrusted networks. This protects specific services from common attacks such as port scanning, Denial of Service (DoS) attacks, or Internet phone scam.

While they may not provide the deep inspection or session awareness of a stateful firewall, they can serve as an effective initial barrier, reducing the load on more advanced systems by blocking simple, high-volume threats before they reach more sensitive parts of the network.

4. They are inherently less vulnerable

Stateless firewalls do not track past traffic or active connections, which makes them less susceptible to certain types of attacks on the firewall’s memory or stored data.

In contrast, a stateless firewall simply compares incoming packets to its pre-defined “allow” and “deny” rules, ensuring that traffic is only allowed into the network if certain conditions are met. This simple method ensures that only authorized traffic enters the network.

By not having to manage the details of each connection, stateless firewalls avoid some of the vulnerabilities that can arise when a firewall tries to remember everything, such as being overloaded during a connection. Different types of DDoS attacksthe attacker floods the system with too many requests.

Stateful firewalls provide deeper inspection and more thorough security, but this introduces additional complexity that can be exploited by attackers. Stateless firewalls completely avoid this risk with their simpler design.

5. Stateless firewalls are cost-effective and affordable

Because they do not require the advanced features of stateful firewalls, such as session tracing or deep packet inspection, their hardware and maintenance costs are significantly reduced. This makes them a viable option for organizations with limited IT budgets or smaller networks.

Stateful firewalls are more expensive due to their advanced features such as integration Intrusion detection and prevention system. These firewalls also require more processing power, memory and specialized hardware to manage real-time traffic analysis and maintain security.

Key Disadvantages of Stateless Firewalls

While stateless firewalls have their advantages, they also have some disadvantages.

1. Minimum package inspection capability

Because it does not track connections, a stateless firewall does not maintain a table of all previous connections that have passed through the firewall. This makes it faster and easier to handle large volumes of traffic, but it has minimal packet inspection.

For example, stateless firewalls can only inspect a single packet based on headers and protocols, which means they cannot see the contents of the packet itself. This makes them less effective at detecting and preventing more sophisticated attacks that can bypass simple packet inspection, such as those using encrypted traffic.

Additionally, due to the lack of connection tracking, stateless firewalls cannot always differentiate between legitimate and malicious traffic. This can cause unnecessary blockage of legitimate traffic, disrupting business operations. It also makes it more difficult to modify the firewall because stateless firewalls are not aware of connection status, so they cannot dynamically allow and deny traffic based on connection status. Learn more about How status checks work.

2. Harder to scale

One of the biggest disadvantages of stateless firewalls is that scaling them can be an absolute nightmare in some situations.

The problem is that stateless firewalls only examine individual packets to determine whether to allow or deny them. This means that as the number of network connections increases, so does the number of rules in the firewall. Therefore, when your network traffic is high, it can be very difficult to manage and maintain.

Unfortunately, with a stateless firewall, you need to create manual rules for every packet that travels over the network. This can result in too many rules to manage, leading to network performance issues, security flaws, and significant management overhead. Learn more about How to establish a firewall policy for your network.

3. Initial configuration is required for normal operation.

Although setting up a stateless firewall is easy compared to a stateful firewall, the process is not the easiest.

Stateless firewalls may require considerable initial configuration to function properly. For example, because they do not maintain connection state, they must rely on other factors (such as IP address and port number) to determine whether an incoming packet is allowed to enter the network.

This means that, in addition to the above filtering rules, some additional settings need to be carefully configured to ensure that legitimate traffic is allowed through while malicious traffic is blocked. Learn more about How to set up firewall correctly.