Network firewalls are intricate, and it’s essential to understand the different types of firewalls and their functions to protect your business from security threats.
How Do Firewalls Work?
Every firewall has the same overarching goal: Protect the network from outside threats.
They monitor incoming traffic and data packets flowing through the system, identifying known patterns of activity that correlate with various attacks.
There are various types of firewalls that have different criteria for intercepting attacks, and the more advanced types of firewalls offer a stronger and more sophisticated level of protection than the basic options allow.
Next Generation Firewall
Among all types of firewalls in network security, one of the strongest options are next generation firewalls (NGFWs). The NGFWs are the most robust, and vary in size and price points to fit the needs of any organizational environment or budget.
These firewalls offer high levels of security and granular control over all data flowing through the internal network, usually combining application level firewall blocking alongside thorough packet inspection that assesses the content of the packet itself. These systems also offer automated visibility to eliminate security threats, and come with optional security add-ons, such as intrusion monitoring, encrypted cloud access or antivirus scanning to further enhance security.
NGFWs allow for flexibility with security deployment, and can run security features – such as IPS and SSL/TLS inspection – individually or simultaneously with very little performance degradation.
Additionally, NGFWs provide streamlined device deployment where all devices within an enterprise’s network are connected through the centralized, internal system – allowing for complete, synchronized protection and reducing the need for numerous contact points throughout the organization.
Some key players in the Next Generation Firewall space include:
- Fortinet FortiGate
- Forcepoint NGFW
- Palo Alto Networks PA Series
- Barracuda F-Series
- Cisco Firepower NGFW
Image source: https://www.fortinet.com/blog/business-and-technology/redefining-next-generation-firewalls
Next generation firewalls offer some of the highest levels of security available, but they also can come with more substantial operating costs and network performance impacts that businesses will need to account for.
Packet filtering firewalls are one of the earliest and simplest forms of the modern firewall. These types of firewalls are built on the idea of data filtering. When information is sent through a connection (via “packet”), the firewall compares each packet to a set of pre-established criteria, usually related to the packet protocol header, IP addresses, packet type, or port number.
If the system detects a known attack pattern based on these criteria, it drops the packets and prevents the connection from being made.
However, the simplicity of the packet filtering firewall cuts both ways. While these firewalls offer a basic standard of security, they can assess packets only on broad sets of criteria, often related to the service they’re being used for or the destination port.
Compared to the other firewall options, this is a fairly superficial way to prevent malicious traffic, and more advanced security features (such as intrusion detection) aren’t typically included.
Circuit Level Gateway
Circuit level gateways are another type of firewall with a slightly different approach. Rather than filtering packets, the gateway creates an intermediary connection between the local and remote hosts.
This connection offers coordinated security across the User Datagram Protocol (UDP) and Transmission Control Protocol (TCP).
In essence, the circuit level gateways only allow traffic that can be verified by the web connection’s TCP handshake. If this verification doesn’t happen, the traffic doesn’t go through.
Like packet filtering, this firewall is simple to understand and deploy – but it does come with limitations.
The firewall can’t perform deep packet inspection, meaning that it can’t assess the actual data being sent through the connection. With this firewall, malware can slip through undetected, if it passes the TCP verification.
On the other hand, its simplicity means that it takes few resources to operate, and network performance impacts tend to be minimal.
Interested in learning more about securing your business? Check out these blogs:
- Cyber Threats You Will Likely Face and How to Defend Yourself
- Practical Cyber Security for Your Small Business
- Critical Cyber Security Strategies for SMEs
Stateful Packet Inspection
Stateful packet inspection (SPI) firewalls are a bit of a hybrid, combining packet filtering alongside tracking the state of each network session, based on pre-established security criteria.
With stateful inspection firewalls, the system monitors both incoming packets and the presence of any TCP connections or any other session-level state information to determine how data can be sent. For reference, stateful inspection firewalls work within the network layer of the Open Systems Interconnection (OSI) framework.
And while the scope of OSI model is too big to get into here, business owners can be assured that this firewall method will offer a much higher standard of security than basic packet filtering.
However, this firewall can damage network performance because it requires more resources.
Application Level Gateway (Proxy Firewalls)
Application level gateways are a sophisticated type of firewall that filters traffic at the application layer rather than the circuit level. This is also known as a “proxy firewall,” as the system usually involves setting up a proxy server to intercept traffic and validate it against a set of security criteria before sending it through.
This approach offers great protection against malicious traffic and threat actors, as it combines essential packet detection with session-level criteria in a simple, hard-to-penetrate framework.
Most critically, the application level gateway proxy prevents malicious users from accessing web applications directly. Of course, like many sophisticated firewalls, the security comes at the expense of system performance.
Get Familiar With the Different Types of Firewalls
There are plenty of providers out there offering various types of firewalls, and each solution has its own benefits and drawbacks to consider. And It’s critical to consider a firewall that meets your security needs, policies, and your business’s cybersecurity strategy.
The implementation of the firewall is just as important. If a firewall is implemented incorrectly it leaves your organization vulnerable and open to threats, and as a best practice, it’s best to reach out to IT consulting experts
Contact us if you’re interested in creating a secure business environment.