How do you compare stateful and stateless firewalls?

1 What are stateful firewalls?

Stateful firewalls are firewalls that keep track of the state of network connections. This means that they can remember information about each packet, such as its source, destination, protocol, and sequence number. By storing this information in a state table, stateful firewalls can match incoming and outgoing packets to their corresponding connections, and allow or deny them based on predefined rules. Stateful firewalls can also detect and prevent attacks that try to manipulate or exploit the state of connections, such as denial-of-service (DoS) or spoofing attacks.

2 What are stateless firewalls?

Stateless firewalls are firewalls that do not keep track of the state of network connections. This means that they only inspect each packet individually, based on its header information, such as its source, destination, port, and protocol. Stateless firewalls do not store any information about packets or connections, and they apply the same rules to every packet, regardless of its context or history. Stateless firewalls are faster and simpler than stateful firewalls, but they are also less flexible and secure.

3 How to compare stateful and stateless firewalls?

When comparing stateful and stateless firewalls, it is important to consider factors such as performance, security, complexity, and compatibility. Stateless firewalls are faster and more efficient than stateful firewalls as they don't have to maintain a state table or perform complex checks on packets. However, they may consume more bandwidth and resources. In terms of security, stateful firewalls are more secure due to their ability to monitor and control the state of connections. They can also detect and prevent attacks that exploit the state of connections, while stateless firewalls are more vulnerable due to their inability to distinguish between legitimate and malicious packets. Stateful firewalls are more complex than stateless firewalls as they require more configuration and management. On the other hand, stateless firewalls are simpler and easier to configure and manage. In terms of compatibility, stateful firewalls are more compatible than stateless firewalls as they can support different types of network protocols and applications. Stateful firewalls can handle protocols that use dynamic ports or encryption, while stateless firewalls cannot.

4 How to choose the best firewall for your network?

When choosing a firewall for your network, there is no definitive answer, as it depends on the size, architecture, traffic, and security requirements. Generally speaking, a stateless firewall is faster, simpler, and cheaper for small or simple networks with low traffic and security needs. Conversely, a stateful firewall is more secure, flexible, and compatible with larger or complex networks with high traffic and security needs. For mixed or hybrid networks with different types of protocols and applications, a combination of stateful and stateless firewalls may be the best option. For instance, you could use a stateful firewall at the network perimeter to protect from external attacks while using a stateless firewall at the network segments to improve performance and efficiency.

5 What are some examples of stateful and stateless firewalls?

The market offers several examples of stateful and stateless firewalls. Common stateful firewalls include Cisco ASA, Check Point, Palo Alto Networks, Fortinet, and Juniper SRX. Examples of stateless firewalls are Linux iptables, Windows Firewall, pfSense, and MikroTik RouterOS.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?