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Over the decades, many different types of firewalls have played an essential role in maintaining network security. By filtering out malicious traffic before it’s permitted to enter network perimeters, firewalls strengthen network security, reduce malware risks, and provide a critical barrier against cyber attacks.
Learning about the different types of firewalls, their functionality, and delivery methods can help ensure your organization uses the appropriate firewalls to protect data, applications, and users.
In this article, we’ll cover:
- Firewall architectures and delivery methods
- Types of firewalls in network security
- How to find the best firewall for your needs
Three Different Types of Firewalls and Their Functions
Firewall Architectures & Delivery Methods
From a structural standpoint, there are three different types of firewalls. In the world of IT, firewalls are deployed as a service, can be software-based, or can be a hardware appliance.
Software-based firewalls operate on a server or alternative device and are also known as host firewalls.
Since software firewalls must be installed on every device requiring protection, they will take up CPU and RAM resources on your devices. Overall, software firewalls provide supported devices with robust protection against malicious content, viruses, and malware.
Additionally, software-based firewalls can:
- Discern different programs active with the host
- Filter inbound and outbound traffic
- Enable or prevent communications to and from one program
Hardware-based firewalls are appliances that function as a secure gateway, protecting devices within a network’s system from external threats.
Unlike software firewalls, hardware firewalls don’t hog endpoint resources. Instead, a hardware firewall includes a physical appliance that has the processing power built-in for the tasks it needs to perform. Also called network-based firewalls, they’re best-suited for medium to large-sized organizations with many devices to protect.
Since hardware-based firewalls run their own operating system, have manufacturer-specific interfaces, and CLIs, they can require greater IT expertise to configure and manage successfully. It’s why hardware firewalls are provided and administered by managed security service providers (MSSPs).
Cloud-based firewalls, or firewalls as a service, are also provided by MSSPs. Organizations that use cloud-based firewalls can track internal network activity along with third-party on-demand environments.
Virtual firewalls are very similar to hardware firewalls; the only main difference being that they’re deployed on cloud architecture.
Overall, cloud-based firewalls are suitable solutions for large or multifaceted enterprises with security gaps or those wishing for a more transparent private network on the cloud.
Being a cloud-based solution, you can scale virtual firewalls easily – letting you minimize overheads or maximize capacity, as your business needs.
Five Essential Features of Firewalls and Their Functions
Firewalls are categorized according to their function and architecture. Here are the five primary features of firewalls you should be familiar with.
1. Packet Filtering Firewall
Packet filtering firewalls are the oldest, most basic, and most inexpensive firewalls.
They operate at the network layer, and they check data packets for their:
- Source port
- Destination port
- Source IP
- Destination IP
Checking data packets against predetermined rules allows packet filtering firewalls to pass or discard packets.
Packet filtering firewalls are virtually stateless, as they monitor data packets individually and without consideration for previously connected packets. Given how these firewalls operate, they provide limited protection against advanced cyber threats, routing attacks, and tiny fragment attacks.
Lastly, since a packet filtering firewall cannot examine the content of data packets, networks are still susceptible to malicious data packets originating from trusted source IPs.
2. Application-Level Gateways (Proxy Firewall)
Proxy firewalls, or application-level gateways, operate as an intermediary between two systems and filter network traffic at the application layer of the OSI network model for a web application.
Their operation entails.
- An external client sends a request to the proxy firewall, the proxy firewall validates the authenticity of the request, then forwards the request to one of the internal servers or devices used by the client.
- An internal device can request access to a webpage, where the proxy device will forward the request.
Since proxy firewalls provide an extra step in the connection process due to all connections routing through the proxy firewall before gaining network access, they have slower connection speeds.
3. Circuit-level Gateways
The primary function of circuit-level gateways is to verify Transmission Control Protocol (TCP) connections and track ongoing sessions.
Similar to packet filtering firewalls, circuit-level gateways perform singular checks with minimum resources to verify connection authenticity.
When connection requests occur, an internal device initiates the connection process with a remote host, establishing a virtual connection on behalf of your internal devices.
A core perk of a virtual connection is that your network’s identity and IP address remain hidden.
While circuit-level gateways are cost-efficient firewalls and hardly hinder an organization’s network performance, they cannot inspect the content of data packets. Should a connection have a legitimate TCP handshake, it’s pretty easy for malware-infected data packets to affect a network.
That is why other firewalls are often used with circuit-level gateways.
4. Stateful Inspection Firewall
Stateful inspection firewalls verify, track, and establish a connection, while also inspecting data packets.
One tier above circuit-level gateways, stateful inspection firewalls create a state table with source IP, source port, destination IP, and destination port after an established connection.
While the added security of these firewalls is robust, they eat up system resources and tend to hinder network performance. As a result, they can be targeted by DDoS attacks.
5. Next-Generation Firewalls (NGFW)
Next-generation firewalls combine the features of multiple firewalls and have enhanced security features that allow them to bypass traditional firewall limitations.
These firewalls are less susceptible to DDoS attacks and allow applications to identify and block attempts to breach data from encrypted applications.
What separates NGFW from other firewalls would be how it is a deep-packet inspection firewall that extends beyond port and protocol inspection and blocks for added intrusion prevention.
Businesses dealing with data compliance standards, credit card transactions, or wanting the best network security to gravitate towards next-generation firewalls.
Which Types of Firewalls Are Best for Your Network Security?
Firewalls are critical for improving network performance, security, and longevity.
By ensuring your business has the proper firewalls in place, you strengthen your organization’s network.
At Fusion Computing, we provide consultations for firewall audits and online security assessments for those unsure which of the various types of firewalls is best suited for their business demands.
Get started today and speak with one of our specialists.