When you hear of the term firewall, you might believe there is only a single type, but that is not the case. There are different types of firewalls, and luckily for you, this is something we aim to explain in this article. You see, we are going to define each type of firewall that is available for the Windows operating system, but not only that, but we shall also describe their main differences.
What is a Firewall?
To be clear, a firewall is a network security tool that is designed to monitor incoming and outgoing network traffic. Additionally, the firewall is capable of permitting and blocking packets of data based on defined security rules.
Different types of Firewalls
We have covered the following different types of firewalls available for the Windows operating system along with advantages and disadvantages:
- Stateful Inspection Firewall
- Stateless Firewall or Packet-filtering Firewall
- Application-Level Gateway Firewall
- Next-Generation Firewall
1] Stateful Inspection Firewall
Not everyone has heard of the stateful firewall, but it is something that exists. It’s the type of firewall that keeps track of and monitors the state of any active network connection. It can also analyze incoming traffic along with looking out for possible data risks.
From what we have gathered, this type of firewall is situated at Layer 3 and Layer 4 of the Open Systems Interconnection (OSI) model.
One of the functions that come with the stateful firewall is the ability for it to prevent malicious traffic from gaining access or leaving the private network. Furthermore, it can monitor the overall state of network communications and detect unauthorized network access attempts.
Advantages of Stateful Firewalls
- Ability to prevent attacks
- Broad logging capabilities
- Will not open a large range of ports to allow traffic
- Connection state-aware
Some of the disadvantages of Stateful Firewalls
- It can be difficult to configure
- Not capable of avoiding application-level attacks
- Some protocols do not have state information
- Maintaining a state table requires additional overhead
2] Stateless Firewall or Packet-filtering Firewall
A stateless firewall is also known as a packet-filtering firewall. What we have here is the oldest and most basic type of firewall currently available. Compared to others, this type of firewall operates inline at the network’s perimeter. We should note that firewalls such as these do not route packets, but instead, they will compare every packet received to a set of predefined rules.
Because it only provides basic security, folks can set it to protect against known threats, but it won’t do good with unknown threats.
Packet-filtering Firewall advantages:
- Does not cost a lot of money to maintain
- Processing packets is done extremely quickly
- Filtering traffic for an entire network can be done with a single device
Packet-filtering Firewall disadvantages:
- In some instances, it can be complicated to configure and difficult to manage
- Logging capabilities are limited here
- When it comes down to application attacks, it cannot avoid them
- Does not support user authentication
- Cannot fully protect against all TCP/IP protocol attacks
3] Application-Level Gateway Firewall
OK, so an application-level gateway firewall, or (ALG) for short, is a firewall proxy that offers network security. It is designed to filter incoming node traffic to particular specifications, which simply means, the only data filtered here is from a transmitted network application.
As for the network applications that can work with ALG, some of them are File Transfer Protocol (FTP), Telnet, Real-Time Streaming Protocol (RTSP), and BitTorrent.
We should point out that ALG delivers one of the highest-level secure network system communications. To explain this better, let us look at a simple example of how things work.
When a client moves to requests access to a server on the network for particular resources, the client will first connect with a proxy server, and from there, that proxy server will establish the connection with the main server.
Application-Level Gateway Firewalls Advantages:
- Traffic logging is made easier
- Network performance is much better
- Hard to enable direct connections from outside the main network
- Supports content caching
Application-Level Gateway Firewalls Disadvantages:
- Impact throughput capabilities
- Impact applications
Read: How to test your Firewall software?
4] Next-Generation Firewall
Finally, we want to talk about the next-generation firewall (NGFW). From what we have gathered, this is a deep-packet inspection type of firewall that can expand beyond port/protocol inspection. Not only that, but it goes beyond blocking to deliver application-level inspection, which is up to Layer 7.
As you might be able to tell, this is a more advanced version of the typical firewall system, but it provides the same benefits all-around. However, unlike the traditional firewall systems, NGFW applies both dynamic and static packet filtering along with VPN support in a bid to secure all incoming connections between the network, internet, and firewall.
Next-Generation Firewalls Advantages:
- More secure than the others here
- Logging is more detailed
- Supports user authentication
- In terms of application-level inspection, this is supported up to Layer 7 of the OSI model
Next-Generation Firewalls Disadvantages:
- Will use more system resources when compared to the others
- The overall cost is more expensive
- To limit false negatives and positives, more fine-tuning is required.
Read: Difference between Hardware Firewall & Software Firewall
Do Firewalls stop viruses?
A firewall is not capable of protecting your computer system from viruses and malware. As stated above, the firewall was created to limit outside access to your network, it makes it difficult, then, for attackers to bypass it to gain access. At the end of the day, then, you will still require an anti-virus program to protect your system from viruses and malware.