While dealing with the various tools used to secure the sensitive data, you must have come across the “Firewall” also. Sometimes, it is also referred to as “Network Firewall.” So what is the Firewall Meaning? And, what are the various types of Firewall? How do all these types of firewalls function, and which one should you choose for the management of cybersecurity of your own business? I have comprehensively explained these topics including what is Firewall Meaning below in this article, so that you may have a clear picture in your mind.
A Firewall is actually a cybersecurity tool that works as a filter to refine the traffic coming onto a network. It can either be software or hardware or even be a cloud-based service. This tool will separate the nodes of the network not only from the internal or external sources of the traffic but also from a special type of application. No matter whether it is software or hardware or even a cloud-based firewall, its main function is to hamper or block the malicious and harmful traffic requests coming to the network protected by it. It only allows legitimate and unharmful traffic and data or information packets.
I hope the information provided above about Firewall Meaning is enough to make you understand the Firewall meaning. Now let’s jump on the next part of this article.
Types of Firewall
After knowing about the Firewall Meaning, we will go on with its types. On the basis of the method of operation and the structure they have, Firewalls are mainly of 8 types. These types, along with their functioning, are explained below one by one:
1) Packet-Filtering Firewalls
These are the oldest as well as the simplest type of firewalls and are not much resource-intensive. Being the most basic and most straightforward type of firewalls, they are easier to be bypassed. And, they will not have a significant impact on the performance of your system because of not being too resource-intensive.
For protecting a network, Packet-Filtering firewalls first make a checkpoint at the traffic switch or router. The information packets that come through that switch or router are then checked by the Firewall without getting opened. Since these firewalls don’t open these data packets, the content packed in them is not inspected. These packets are just inspected for their IP address, destination, type of package, port number or other similar information. The packets not passing this inspection are not allowed to enter. They are discarded by the Firewall.
2) Circuit-Level Gateways
Circuit-Level Gateways are another type of simple Firewall that is also not much resource-intensive. These firewalls work as a virtual connection between the internal users of the network and the remote host.
These types of firewalls just verify the TCP (Transmission Control Protocol) handshake. And, by making this verification, the firewalls get to have a conclusion on whether or not the session from which the data packet is coming is legitimate. If the packet is judged to be legitimate after this verification, it is allowed, otherwise dropped or discarded.
These types of firewalls are not considered to be much protection for your business. That’s because they only inspect the TCP handshake of the packet rather than inspecting the packet itself. Hence, in case, there is a malware inside a packet having an excellent TCP handshake, the packet will pass the inspection and will be allowed to enter.
Also, read more about the comprehensive comparison of IDS VS. Firewall VS. IPS.
3) Stateful Inspection Firewalls
Another one of the various types of firewalls is Stateful Inspection Firewall. And, these firewalls will have more impact on the resources as compared to both of the types of firewalls mentioned above. Sometimes these firewalls are also referred to as “Dynamic Packet Filters.”
As far as the functioning of these firewalls is concerned, they will inspect both the TCP handshake as well as the data packet itself. Thus there will be a higher level of protection due to this combination of verification of TCP handshake and verification of packet.
4) Proxy Firewalls or Application-Level Gateways
A proxy firewall is a cloud-based firewall that filters or refines the incoming traffic by working at the application layer. However, this type of Firewall will significantly slow down the speed of transfer of data between the source of traffic and the network.
First, the proxy firewalls connect themselves to the traffic source so that they may check the data coming to the network before allowing it to enter the network. During this inspection, not only both the TCP handshake and packet are inspected, but the content packed inside the packet is also inspected. Thus it is also confirmed that there is no malware even inside the packet before letting it enter the network.
Thus after checking the incoming data packets or traffic in the way as mentioned above, the packets that are found to be legitimate are allowed to make the connection with the network, and others are rejected or discarded. As mentioned above also, these firewalls work on the application layer. Hence they are also referred to as the “Application-Level Gateway.”
5) Next-Gen Firewalls
It is worth noting that most firewalls that have been recently launched are being considered as the Next-Gen Firewalls. They are generally the combination of both the deep packet inspection and the stateful inspection firewalls. However, there is no specific definition of such types of firewalls.
Next-Gen firewalls are the most popular type of firewalls at present. The reason is that malware, nowadays, is very complex. And, it is challenging to protect the networks against such malware without the use of the Next-Gen firewalls. These firewalls are more advanced and more sophisticated ones as compared to the firewalls of the old days.
When it comes to the features of functioning to be possessed by a firewall for it to be considered as a Next-Gen Firewall are as follows:
- It should be able to inspect surface-level information like IP address, port number, packet type, etc.
- There should be an inspection of the TCP handshake also.
- The Firewall should be able to make the deep-packet inspection as well.
So keeping in mind the features mentioned above, you can determine whether a particular firewall product is actually a Next-Gen firewall or not.
6) Software Firewalls
In case you intend to provide in-depth defense by isolating all endpoints of the network from one another, there will be a need to install a firewall individually on each local device. This type of Firewall is called a Software Firewall.
When it comes to installing software firewalls individually on each asset of the network, you may need to have different types of software firewalls for different assets. Moreover, maintaining different firewall software for different assets consumes a lot of time and is very complicated also. So you should consider all these drawbacks before going ahead with Software Firewalls.
7) Hardware Firewalls
Where there is a need for protecting a network against the external malicious traffic; a firewall providing perimeter security will be required. And, this kind of security can be provided with the help of a physical appliance which would function as a traffic router for intercepting the data or information packets before letting them connect to your network. Such physical appliances are called hardware firewalls, and they help in protecting the endpoints of a network against security risks.
As mentioned above also, hardware firewalls protect your network against external malicious traffic or risk. But there are the chances of internal risks or attacks. And, different hardware firewalls from various manufacturers come with different capacities to fight against risks or malicious attacks. Hence you will need to choose the best one after smart research.
8) Cloud Firewalls
A cloud-based service used to provide a firewall for protecting a network against harmful traffic is called a cloud firewall. It is a scalable firewall because you can increase its capacity to filter or refine a larger volume of traffic as your business requirements increase or rise.
Setup of a proxy firewall is made use of in cloud firewalls. That’s why some people also consider them as synonymous with the proxy firewalls. Moreover, you will also have perimeter security for your network with the cloud firewalls.
Security Threats For Packet-Filtering Firewalls And Methods To Avoid Them
The security threats to the packet-filtering firewalls are as follows:
- There are cases when an outsider tries to send some data packets with the same IP address as that of one of the internal IPs of the network. Thus it helps the malicious traffic easily pass the inspection made by the Firewall. And it causes a threat to your network. And, when it comes to the method to avoid this type of threat, the Firewall can fight against it only if it is capable of discarding the packets coming from the incoming side with the same IP address as that of one of the internal IP’s.
- In case, the packet size is larger than the size accepted by the Ethernet, etc., it can be carried ahead only if it is fragmented. So taking advantage of this weakness, the attackers fool the Firewall by intentionally creating the fragments of the data packets and send them to the Firewall. They make use of the TCP protocol characteristics. So the solution or prevention for this kind of attack to your Firewall is possible if your Firewall can discard all of the data packets that are fragmented and make use of the TCP protocols. Thus it will end up allowing only the legitimate data or information packets to your network.
- Sometimes attackers try to fool the network firewall by specifying the route that the packets have to take. And, your Firewall can prevent this kind of attack to your network by discarding all of the data packets that make use of the path addressing option.
Which One To Choose?
Now that you are very well aware of the various categories or types of firewalls, here is another question. And, the question is what type of Firewall you should choose for your own business? Which one is best for you?
Actually, no single layer of Firewall would be individually enough to provide the full protection to your network against all types of malicious attacks. Rather there must be a number of layers for providing full protection. You should provide these security layers both at the perimeter as well as between different assets of your network.
As mentioned above, for protecting the individual assets of the network, you can make use of the software firewall. So you can go ahead with it at the individual asset level for separating one asset from the other. And, on the other hand, either cloud or hardware firewalls can be used for protecting at the perimeter of the whole network.
And as far as the selection of a particular firewall is concerned, you will have to make the final buying decision on various factors like resources possessed by your organization, network capabilities, compliance requirements, etc.
When it comes to providing extra protection to the network by providing additional firewalls, it can be done by making an extra in-depth defense. Such an in-depth defense will offer isolation to every asset of the network. And, a network with such a strong defense layer cannot be easily disturbed. The attackers will have to make extra efforts so as to hack your system and to steal your important and sensitive data.
Final Words on Firewall Meaning
There is no doubt that, with the emerging uses of the internet, the whole world has come closer. But it has also gifted a lot of security issues that you will need to have a powerful mechanism to deal with. Various types of firewalls are going to stop the attackers from stealing and destroying your valuable data and help you protect your network.