A firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted internal network and untrusted external network, such as the Internet. 

Firewalls can be hardware- or software-based. Hardware-based firewalls are usually incorporated into a router or network switch and provide a first line of defense against network attacks. Software-based firewalls are usually installed on servers and workstations and provide an additional layer of security.

There are two main types of firewalls: traditional firewalls and next-generation firewalls (NGFWs). 

Traditional firewalls, also known as stateful inspection firewalls, inspect traffic based on a set of predefined rules. 

NGFWs, on the other hand, are designed to provide more comprehensive protection by inspecting traffic at multiple layers and using a variety of techniques, such as deep packet inspection and application-aware filtering.

While both traditional firewalls and NGFWs can be effective in protecting networks from external threats, there are some risks associated with traditional firewalls that can be mitigated by using NGFWs.

Risks Associated with Traditional Firewalls 

1. Limited Visibility and Control

Traditional firewalls provide limited visibility into network traffic and can only control traffic at the network layer. This means that they are not able to inspect traffic at higher layers, such as the application layer, where many attacks originate. As a result, traditional firewalls can miss attacks that use legitimate protocols to bypass security controls.

2. Complex Rule Sets

Traditional firewalls require complex rule sets to properly control traffic. The more rules that are added, the more difficult it becomes to manage the firewall and the greater the risk of human error.

3. Slow Performance

Traditional firewalls can slow down network performance because they inspect every packet that passes through the firewall. This can be a particular problem for high-traffic networks.

4. High Cost

Traditional firewalls can be expensive to purchase and maintain. The cost can be even higher if the firewall needs to be upgraded to support new features or address performance issues.

Advantages of Using Next-Generation Firewalls 

1. Comprehensive Protection

NGFWs are designed to provide comprehensive protection by inspecting traffic at multiple layers and using a variety of techniques, such as deep packet inspection and application-aware filtering. This allows NGFWs to detect and block a wide range of attacks, including those that use legitimate protocols to bypass security controls.

2. Improved Visibility and Control

NGFWs provide improved visibility into network traffic and can control traffic at multiple layers. This allows administrators to more effectively monitor and manage network activity.

3. Simplified Rule Sets

NGFWs typically have simpler rule sets than traditional firewalls. This makes them easier to manage and reduces the risk of human error.

4. Enhanced Performance

NGFWs can improve network performance by offloading traffic inspection to dedicated hardware. This frees up resources on the firewall itself, which can improve its overall performance.

5. Reduced Cost

NGFWs can be less expensive to purchase and maintain than traditional firewalls. The cost savings can be even greater if the NGFW is able to replace multiple traditional firewalls.

NGFWs offer a number of advantages over traditional firewalls, including better protection against modern threats, easier configuration and management, and better support for multiple devices.