We all know what a firewall is: it stops a real fire from spreading. However, its virtual counterpart operates similarly. For over 25 years, a firewall has been the first line of defense in network security. It works as a filter that controls what data leaves or enters devices, isolating networks from external threats. But does it make you secure enough? What are the risks of not having it? Let’s find out.
What is a firewall?
A firewall is a cybersecurity tool — firmware or software — that monitors incoming and outgoing traffic. The tool either permits or blocks data packets over your network by relying on pre-established sets of security rules. The main goal is to isolate your device from malicious traffic requests while letting authorized traffic pass.
The term “data packet” plays a significant role in the digital world. A data packet is a small unit of information that travels from a source to a destination point. Unfortunately, these network data transfers aren’t foolproof. If corrupted or lost during the transmission, malicious third-parties can intercept and modify them for nefarious purposes.
How does a firewall work?
A firewall “sits” at the front line of a network and acts as a communication intermediary. Its job is to carefully analyze all traffic messages between your computer and external sources. In case the message fails to meet the defined security criteria, the security system instantly drops it. Hence, it prevents malicious third-parties from breaking into your system.
It also performs the following tasks:
- Protects your resources
- Permits and blocks access
- Controls network traffic
- Records and reports suspicious traffic requests
- Acts as an intermediary between you and external sources
Types of firewalls
There are software, hardware, and cloud-based firewalls. Each format serves a different but essential purpose. A hardware firewall is a physical appliance, like a broadband router, which intervenes between your network and gateway. A software one is an internal program that works on each device individually. In contrast, a cloud-based system is a proxy-based server that is capable of managing substantial traffic loads.
Maintaining separate firewalls on individual devices can get complicated and time-consuming. Hence, hardware and cloud-based filtering tools are better choices for corporate networks. However, casual users can fully benefit from software tools to secure individual endpoints.
Firewall types divide into a few distinct categories based on their general architecture and method of operation. Here are the main ones:
- A packet-filtering firewall is the oldest and the most basic type of network filtering architecture. It inspects data packets from the router and checks only the basic information, like the request’s destination, origin IP address, and port number. The good news is that this particular type isn’t very resource-intensive. However, since packet-filtering systems are incapable of inspecting packets’ content, they are relatively easy to bypass.
- Circuit-level gateway is another simplistic firewall type. It works by checking the transmission control protocol (TCP) handshake. This handshake verifies if the data packet comes from a legitimate source. Circuit-level gateways are also extremely resource-efficient. However, circuit-level gateways are also incapable of checking the inside content of a session packet. Therefore, if it holds malware, but has the right TCP handshake, a malicious session packet can pass.
- Stateful inspection firewalls use both — packet inspection technology and handshake confirmation — to safeguard the network. Such a combination creates a greater level of security than either of the previous two. However, this type of network filtering does put more of a strain on computing resources at the same time.
- Proxy firewalls/application-level gateways operate at the application layer. They also rely on both parameters: data packet and TCP handshake protocol. Additionally, these gateways are capable of performing deep-layer packet inspections. They can check the actual contents within the session packets to verify that it contains no malware. Moreover, once the check-up is complete, the firewall separates the data packet between you and the external source. As a result, it creates a layer of anonymity and protection to your network. However, due to the extra steps in the data transmission processes, these gateways can create significant slowdowns.
- Next-generation firewalls also perform deep-packet inspections, TCP handshake checkups, and inspect surface-level information of individual packets. These robust security tools often contain sophisticated technologies to isolate you from external threats. For instance, a next-gen system may have an Intrusion Prevention System (IPS) that automatically stops cyberattacks against your network.
Is a firewall enough to stay safe online?
Without a doubt, firewalls are useful network security tools for raising the level of protection for your devices and data. However, they do face some shortcomings. Since they operate based on predetermined rules, they can’t predict what threats might come down the pipeline. Therefore, if you haven’t set the right rules, your firewall doesn’t know how to defend against them. It’s a reactive system, not a proactive one. It needs to work together with other solutions to provide you with comprehensive protection.
Using a properly configured firewall and VPN encryption can give you the best results. Similarly, VPN allows you to send and receive data across the network safely. It encrypts the contents of the packets and reverses them to unreadable pieces of information. Furthermore, it changes your IP address to help you stay private when browsing the net. You can get these and a lot of other benefits with the online security tool right here:
Former chef and the head of Atlas VPN blog team. He's an experienced cybersecurity expert with a background of technical content writing.