Different Types of Firewalls

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Different Types of Firewalls

Yash Kushwaha
Last updated on November 16, 2022

    What defenses do you have against malicious traffic and software? Do you have a firewall to secure your infrastructure?

    The conversation around technology focuses on security. It is important to secure the data and websites and enable the latest security methods for better results and added protection.

    As most businesses are going digital, it has become imperative for them to protect their infrastructure from external threats. There are numerous solutions for safeguarding infrastructure in this modern age. One of the solutions is utilizing a firewall. It is one of the oldest and most straightforward, practical, and affordable data security solutions that has been employed since the 1980s.

    A firewall is basically a security device that filters traffic on a network and blocks unauthorized access to computer systems connected over a network. Over decades, it has been serving as an essential tool in an enterprise network security arsenal.

    This blog will take a detailed look at firewalls and their types. Also, we shall walk you through a few popular firewall delivery methods, how you can select the perfect firewall and the pros and cons of firewalls.

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    What is a Firewall?

    It is a security system or device that monitors and manages network traffic following a set of security criteria. It is present between the internet and a trustworthy network since the internet is frequently untrusted. So, we can say that it acts as an intermediary between an insecure internet and a secure network consisting of multiple interconnected computer systems. The most common use of this security device is in business networks to safeguard them from cyber threats .

    It is the responsibility of a firewall to either permit or deny incoming and outgoing traffic to pass in or from a network. It is of three different types, namely software, hardware, or both. Each type possesses different functionality but serves the same purpose.

    A hardware firewall, often referred to as an appliance firewall, is basically a physical device that acts as a bridge between a computer network and a gateway. Meanwhile, a software firewall, commonly known as a host firewall, is simply a computer program installed on a system and works through port numbers and other installed software programs.

    Creating walls between the buildings to prevent fire was the practice that gave rise to the word "firewall." Network firewalls employ similar methods to prevent internet threats.

    In a private network, they act as gates or gated borders to control the flow of legitimate and illegitimate web traffic. The phrase describes structural obstructions that prevent fire spread until assistance arrives. Like web traffic management, network security firewalls are widely used to stop the spread of online dangers.

    Importance of a Firewall

    Any traffic trying to enter your systems can access networking that lacks protection. We should always track network traffic, dangerous or not. Hence, one should always install an up-to-date farewell in their systems.

    When linking personal computers to other IT systems or the Internet, many practical prospects become available. Technology that makes cooperation, resource sharing, and creativity easier should also consider technology that makes collaboration easier online and improves security. If users link their computers to a network or the Internet, they risk becoming prey to malware, online fraud, identity theft, and hacking.

    The following details will help us better to understand the significance of firewalls.

    Feature 1: Keeping Track of Network Traffic

    To keep the systems secure, firewall security begins with efficient network traffic monitoring based on pre-established rules and filters. The following security procedures are used when monitoring network traffic:

    1. Incoming network traffic blocking depending on source or destination

    The majority of firewalls have this function, which allows them to restrict incoming traffic by

    investigating its origin.

    2. Block network traffic based on content

    The upcoming security devices have advanced systems which identify the incoming threats and harmful files and block them accordingly. For Example, the firewall with an in-built virus scanner will filter out the files it feels are harmful. Also, firewalls that work with emails will sort different and unwanted emails accordingly.

    3. Report on firewall activity and network traffic

    Along with the security that firewalls provide by filtering network traffic, many of them come with a reporting mechanism that reports you on various activities. They include who tried to enter your network, who tried to access the restricted information, and many others.

    4. Outgoing network traffic can be blocked based on the source or destination

    There are many firewalls that also restrict and filter the data between your internal work and your internet. The firewall will restrict access to certain websites. For example, Schools use these kinds of measures to restrict students from visiting certain websites.

    Feature 2: Prevents Spyware and Virus Attacks

    With ever-increasing cyber threats, it is important that one employs the best protection to secure themselves. Cybercriminals are devising new ways to attack the system. Be it a virus attack or malware attack, or some new type of DDoS Attack. It is important that we are prepared for it. The easiest way for an attacker to gain access to your system is through malware. Hence, the firewall can play a crucial role in protecting against malicious malware attacks.

    Feature 3: Preventing Hacks

    Cyber hazards are widespread and changing quickly. Your data, emails, systems, and other critical information are protected by firewalls from hackers. They can either completely block a hacker or force them to select a more open victim.

    Feature 4: Encourages Privacy

    A system without a firewall will accept every connection into the network from anyone. So, having one protects the data and creates a trustworthy environment for privacy. Without it, there would be no way to identify incoming threats. Because of this, criminal users can access your devices and compromise your privacy. To protect your network and the personal information on your computer from cybercrime, it's imperative to make use of the available defenses.

    Types Of Firewalls

    Besides hardware and software types, there are many other types of firewalls available out there. Each has its own features and provides a different level of security. Let us discuss each type with its pros and cons.

    1. Packet Filtering Firewalls

    They run inline at intersections where devices like routers and switches work. They don't route packets; instead, they examine each one against a set of pre-established criteria, for example, the allowed IP addresses , packet types, ports, and other data from the headers of packets. Difficult packets are typically dumped, which means that they are not sent and are finally removed.

    Even though packet filtering is a cheap firewall, it may not always offer the level of security that is required for all use cases. Packet filtering offers a fundamental level of security that can give protection against known threats for small or budget-constrained businesses.


    • Efficient and fast in scanning traffic.
    • Cheap
    • Filtering the network requires only a single device.


    • It is ideal for every network
    • It can be easily spoofed

    2. Stateful Inspection Firewalls

    An application that maintains data from previous interactions and occurrences is "stateful" in computer science. A stateful firewall employs information about open connections stored in its database to assess incoming and outgoing traffic rather than inspecting each packet individually.

    It is a kind of packet filtering, also known as dynamic packet filtering, that controls the movement of data packets. In addition, it inspects whether or not packets belong to a specific session or not. If the session is well established between two endpoints, only then this type of firewall enables communication; otherwise, it blocks the communication.


    • Offers high order of control over data
    • Offers logging capabilities.
    • Not depend on multiple ports.


    • Expensive as compared to other options.
    • Interferes with the speed of the network and performance.

    3. Firewall-as-a-service (FWaaS)

    Firewall-as-a-Service is a more contemporary concept for offering firewall functionalities through the cloud (FWaaS). This service is also known as a "cloud firewall."

    FWaaS builds a virtual wall around cloud platforms, infrastructure, and applications like the way traditional firewalls enclose an organization's internal network. When protecting cloud and multi-cloud assets, FWaaS is frequently more effective than conventional ones.


    • Provides an enhanced layer of protection.
    • A great solution for cloud-based users.
    • Easily customizable.


    • Expensive to implement.
    • Has network latency issues.

    4. Next-generation firewalls (NGFW)

    To battle threats at various layers of the OSI model , NGFWs combine traditional firewall capabilities with several added functions. It combines packet inspection, stateful inspection, deep packet inspection ( DPI ), antivirus, malware filtering, and network security systems, such as IDS / IPS .

    NGFWs thoroughly inspect packets compared to traditional firewalls. Deep inspection can, among other things, look at the packet payloads and the apps the boxes are accessing. This makes it possible for the firewall to apply filtering rules more precisely.


    • Provides more accurate insights.
    • Is relatively more secure.


    • It is a complex process to integrate NGFW into corporate systems.

    5. Web Application Firewalls (WAF)

    While traditional firewalls shield private networks from harmful web apps, WAFs help protect online applications from malicious users. A WAF helps to safeguard web applications by filtering and monitoring HTTP traffic between a web application and the Internet.

    It often protects against attacks like file inclusion, SQL injection, cross-site forgery, and cross-site scripting (XSS).


    • Provides real-time monitoring.
    • Easy to use.
    • One-stop solution for cloud


    • Costly if used for a single consumer.

    6. Application-level Gateways (Proxy-Based) Firewalls

    These proxies act as middlemen between clients and servers. Before connecting to the target, clients connect to the firewall. It then takes requests from the client and transfers them to a web server by pretending to be the original client. This way, it protects the identity and other information of the client from the outside world, thereby protecting the network from external threats.

    Further, when a web server tries to respond to a request from a client by sending the requested data packets, the firewall will intercept, inspect the packets, and then relay them to the client via a different connection. A proxy-based firewall effectively blocks direct links between the client and server.


    • Protects user identity.
    • Provides a much deeper and fine level of control and security for the organization.


    • It is costly
    • It interferes with the network and its working.

    7. Circuit-level gateways

    Circuit-level gateways operate between the transport and application layers of an Open Systems Interconnection (OSI) network model, such as the session layer, and offer TCP and UDP connection security.

    Circuit-level gateways monitor TCP handshakes and other network protocol session initiation signals over the network. This is because they are created between the local and distant systems to determine whether the session being launched is valid — whether the remote system is regarded as trusted. This is another reasonably quick method of identifying malicious information. However, they don't check the packets themselves.


    • It accepts only requested transactions. All other traffic is rejected.
    • Very easy to set up.
    • User-friendly and easy to manage.


    • No application layer monitoring.
    • Requires regular updates.

    Firewall Delivery Methods

    As we know, technology is ever evolving. This also affects the deployment and delivery method of a firewall. With the latest development and improvements, we can now deploy firewalls as hardware appliances, software-based approaches, or as a service.

    • Software-Based Firewall

    Also called a host firewall, it runs on a server or other devices. We install host firewall software on every device that we aim to secure. Due to this, they use a portion of the host device's CPU and RAM.

    Software-based firewalls provide the best protection for individual devices, protecting them against viruses and other harmful content. They can distinguish between the several hosts' running programs and filter incoming and outgoing traffic. With the accurate level of control offered, they are feasible to permit communications to/from one program while prohibiting them to/from another.

    • Cloud/Hosted Firewalls

    Managed security service providers (MSSPs) offer cloud-based firewalls. They are commonly referred to as "firewall as a service." We can configure this hosted service to track internal network activity and external on-demand settings. They are an excellent option for large or distributed enterprises with security resource shortages because an MSSP can fully control them.

    Also, they might be helpful for smaller companies with limited human and technological resources. With easy accessibility and high security, cloud-based firewalls are now a go-to option for the enterprise.

    • Hardware-Based Firewalls

    These are the types of appliances that provide a secure network gateway between the devices that are inside and outside the network boundary. Because they are standalone appliances, hardware-based, also known as network-based, firewalls do not consume the host devices' processing power or other resources.

    They are ideal for medium- and large-sized companies that need to secure various devices. Configuring and maintaining them requires in-depth technical knowledge and a lot of effort.

    Which is the Best Firewall for your Organization?

    We must select the proper firewall for the organization. To do so, it is essential to keep many points and aspects in mind. Costing of the firewall, architecture, and reliability are some of the critical factors one should consider.

    Some other aspects one should consider are as follows:

    • What types of traffic checks are essential? While some programs might need to monitor all content of packets, others filter data packets depending on their source/destination addresses and ports.
    • How does the architecture of the company itself relate to the firewall? Consider whether you need the firewall to defend a web application or a low-profile service exposed on the internet. Also, take into account how the inclusion of a firewall will affect the architecture and what additional changes we need to make for the maintenance.
    • What do the firewall's technical goals entail? Can a firewall with fewer features and capabilities perform better than one with more features and capabilities that are not necessary? Also, what is the cost difference between the firewalls, and is it worth the extra money?

    Finding a perfect firewall that fulfills all the criteria is difficult. Most firewalls generally provide a mix of all the perks, and selecting the one which suits the company most is difficult. An NGFW, for instance, might combine new capabilities with a few from stateful inspection firewalls, application-level gateways, and packet filtering firewalls.

    Understanding the architecture and operations of the private network to be safe is the first step in selecting the best firewall. Still, it also requires knowledge of the various firewall types and policies that work best for the enterprise.

    One should never forget that a poorly designed firewall may sometimes be worse than having none at all because it creates a dangerously false sense of security while offering minimal to no protection. Hence, it is essential to select the best one that provides the best results.

    Advantages and Disadvantages of a Firewall


    • Virus protection : A firewall is a security tool that guards a computer by creating a barrier between the machine and undesirable sources. It shields computers from virus damage and stops all trojans using their pre-set criteria.
    • Monitors traffic : The tool keeps an eye on all sources and traffic that can impact the computer and block any potentially harmful or undesired sources.
    • Control hacker activity : As hackers are constantly engaged in hazardous operations online or on systems, this security tool provides security for those who wish to abuse or access various sources.
    • Protect Privacy : The tool provides security to protect personal information from hacking. It provides anonymity and blocks any undesirable websites.


    • High price : Hardware firewalls are more expensive than software ones, and their upkeep is also costly. Therefore, later ones are less expensive and usable for private purposes.
    • Attacks by malware are possible : Sometimes, you may need an anti-virus program though you leverage a firewall because it is alone not insufficient to defend against malware attacks.
    • Effects on Performance : Even while running in the background, a firewall can impact how quickly RAM and processing power are used. Consequently, the system's overall performance declines, although the hardware firewall has a slightly lesser impact.
    • Maintenance : Due to the firewall's complexity, many significant organizations must pay IT departments and specialists to keep it updated.


    This was all about the different types of firewalls. With the fast-changing environment and increasing security risks, it is essential to use the best options available in the market and secure our systems. A firewall is among the best security solutions or devices. With different types available, we recommend you choose the one that best fits your organization’s needs.

    We hope you enjoyed this article and gained insights from it.

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    By blocking malicious or excessive network traffic, firewalls defend your computer or network from outside cyberattacks. Additionally, they can stop harmful software from connecting to a computer or network over the internet.

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