Here in this article, we will explain 6 different types of firewall used to protect the computer and its network system for intrusion and hackers.
What is a firewall?
While talking about internet and security, we all have come across the term firewall, which is a kind of network element (either software or hardware or both) that protects our computers or network from malicious activities. A firewall is not a brick-and-mortar wall with a fire burning around it, but it is actually something that Keeps your computer, and the programs running within it safe. It also prevents the computer or certain programs on a computer from accessing the internet, or stop specific packets, which can also be used for malicious activities. Talking about Windows, it has its own Firewall, however, you can even depend on a third-party firewall and you can get one using third-party antivirus software, for a personal computer.
Talking about firewalls, there are different kinds of firewalls available and each of them works at its level to keep your computer safe in the long run. So, if you are looking for maximum security for your computer and your complete system of computers, or a network, you should know about how different kinds of firewalls work at its own level to deliver an optimum level of security. Depending upon your work, you can even implement those firewalls in your own system or organization, to keep them safe.
So without any further delay, let’s get started with the different kinds of firewalls that you will often come across while dealing with computers and security.
Packet filtering firewall
Among the different types of firewalls available, the packet filtering firewall does its job basically at the junctions, like the router, switch, hub and other network components. It then compares the packets with some known patterns to make sure, the packers and not meant to harm the computer or the devices connected to the network. Packet filtering Firewall actually does not route any packets, however, it will automatically drop the packets without reporting its presence if it is found malicious in some way or the other. Packets are dropped or reported malicious by looking at the IP address, port number and associated information In the packet header.
As packet filtering firewall does not inspect the content of the packet altogether it can serve the basic level of security by inspecting the packet header, which can be useful in many circumstances. Packet filtering firewall is great for small network however, if you are having a big network, packet filtering firewall can go more complex and will not deliver optimum performance. Besides that, as a packet filtering firewall does not keep any logs, it is a big drawback, and networks configured with packet filtering firewalls are vulnerable to spoofing attacks.
Circuit-level Gateway firewall
The circuit-level Gateway firewalls work in a different way and it inspects the TCP handshakes and other ways of network initialization to make sure that the remote devices or the servers are trusted. Packet level Gateway Firewall will also inspect whether the local system has permissions to connect to the remote server show that malicious activities do not take place. In the case of circuit-level Gateway firewalls, the firewall does not inspect the packets altogether, or the contents, which means it also doesn’t guarantee maximum security.
However, if you are looking for the best network performance, choosing a circuit-level gateway firewall can be the best choice for you. Circuit level Gateway firewall isn’t capable of filtering packets as per the content, which is a major drawback for this particular firewall. But the fact that it is more efficient in processing traffic compared to that of application-level firewalls, is also something that most users and network admins find in handy.
Stateful inspection firewall
The third major type of Firewall is a stateful inspection firewall, and it inspects the packets in a deeper way, which eventually ensures, the packages that are getting transmitted, is a part of one or more establish the connection to the remote server(s). So, besides considering the packet headers, the firewall also ensures that the packet isn’t coming from any unauthorized source that might harm a system in some way or the other. A stateful inspection firewall does its job in the network layer of the OSI model and it is considered more reliable compared to the other kinds of firewalls that are available.
However, just like the moon has scars, a stateful inspection Firewall will affect the performance of your network as it requires more processing power compared to the activity of other types of firewalls available. A stateful inspection Firewall is also a difficult task to setup. Stateful inspection firewalls can be a shield against denial-of-service attacks, and can also operate with fewer ports, besides keeping the system safe from attacks that have the ability to exploit protocol vulnerabilities.
Application-level gateway firewall
This type of Firewall also known as a proxy firewall inherits some properties of packet filtering and circuit-switched firewalls. In case of the application-level gateway firewall, the packets are filtered with certain characteristics of the packets and the network connection established, like the HTTP request string. An application-level gateway offers more security to a computer system, as all the applications connected to the network should be first connected to the proxy, which eventually hides the actual IP address so that the attackers do not consider the system vulnerable by not being able to recognize the system.
An application-level gateway firewall can be useful to prevent computer systems from attacks, which cannot be tracked down in the network and transport layer of the OSI model. However, an application-level gateway firewall isn’t a child’s play to set up. Besides that, it also requires a lot of processing power to operate application-level gateway firewalls, which means, it isn’t a feasible solution for all computer networks out there. As, in application-level gateway firewalls, all the applications should be first connected to the proxy, it can sometimes increase latency.
If you are looking for additional security, a next-generation firewall offers the functionalities of traditional firewalls, along with additional functionalities like intrusion detection and prevention, efficient malware scanning and a lot more. The next-generation firewalls are also capable of monitoring network protocols from the second layer, i.e. the data link layer of the OSI model through the top or application layer of the OSI model.
Even though the next-generation firewalls are more efficient, setting up this type of firewall requires huge investments, and most enterprises might not need all the features of a next-generation firewall. Next-generation firewalls also implement deep packet inspection, which means, the firewall also looks at the actual data, each packet is carrying, which eventually ensures the best possible security. This can though take a toll on the network performance, but the high level of security is the best gift that you get in return.
Choosing the right firewall
Now, if you are at the brink of choosing a firewall for your requirements, the answer to this question actually requires to question yourself about what exactly you need. The requirements vary from company to company, and, it also depends upon what exactly the firewall will be configured to safeguard. Besides that, you should have a precise idea of your organization’s architecture to help you understand what level of security you want, and how exactly it will work within your organization.
There are even some customized firewalls, which can implement features from different firewalls to address certain requirements of certain architectures used in different organizations. Choosing or implementing the right firewall is very important, because a firewall not configured properly may be as bad or even worse than having a firewall at all.
So that was all that you should know about the different types of firewalls available. Do you have any questions in mind? Feel free to comment on the same below.