TL;DR
Firewalls serve as the first line of defense between your internal network and external threats, using a combination of software and hardware to inspect and filter traffic. With 10 distinct types — from basic packet filters to next-generation unified threat management solutions — organizations can tailor protection to their specific risk profile. While no firewall is infallible, deploying and correctly configuring one is a non-negotiable baseline for any security strategy.
What is a firewall?
A network firewall creates a barrier between your system and external sources. In essence, it keeps damage from the outside spreading and harming your valuable internal data. Think of your servers, datasets, and resources as your company's treasure. You should do everything you can to protect it from snoops and thieves. A firewall helps you do just that.
A firewall is made of software, hardware, or a combination of the two. No matter what it looks like or how it's made, your firewall should:
- Inspect. Traffic both entering and exiting your system should be closely examined, byte by byte.
- Decide. You define a set of actions or characteristics you'll allow. The traffic is compared to your rules.
- Act. If the traffic adheres to your rules, it's allowed. If not, it's rejected.
When functioning properly, a firewall blocks some kinds of harmful traffic while allowing the good work to move forward unimpeded. And it's important to remember that firewalls protect you from things your staff might do.
Depending on how you configure it, your firewall could protect your:
- Server. A hacker tries to move in and see or steal your data. A firewall blocks their access.
- Client. Someone in your system gets a faulty email and tries to download an enclosed file. Your firewall blocks the download.
These are critical protections that can keep you a step ahead of danger. A firewall makes them possible.
What are the 10 types of firewalls?
Almost every company in business today has a firewall. And every one of those companies has different needs, requirements, and assets to protect.
When every company needs something a little different, the market to create new products explodes. These are just some of the firewall solutions you could choose from to protect your company:
| Firewall Type | How It Works / Key Characteristic |
|---|---|
| Application Layer 7 | Sort traffic based on its contents and its destination. Block any traffic based on rules you define. |
| Connection tracking | Examine the conversation between two sources using knowledge of the Internet Protocol (IP) addresses they've used before. |
| Endpoint | Examine data packets against rules you've crafted. |
| Network address translation (NAT) | A NAT can hide individual IP addresses, blocking scammers from understanding how your server works. This solution is technically not a firewall, but behaves like one. |
| Next-generation | Tap into intrusion prevention, threat analysis, and more with one product. |
| Packet filter | Rules dictate what packets must be examined and what should happen if a problem is found. |
| Web application proxy | Rules dictate how traffic works for one specific application. |
| Stateful inspection | All activity within an open connection is monitored, and filtering rules dictate what should happen. |
| Unified threat management | All activity in open connection is monitored, and the system also looks for evidence of virus attacks. |
| Virtual | Traffic bouncing between physical and virtual networks is monitored. |
You may have one, some, or all of these types of firewalls in play as you protect your company. Firewalls can also be used for external applications. When a firewall is used to protect external properties, they are called "web application firewalls".
Why is a network firewall so important?
Nearly 95 percent of companies have firewalls now, and most of them say these tools are a critical part of their infrastructure. Servers are made to connect, and the open transfer of information is part of almost every business model. If you don't have a firewall, it's time to get one.
Why proper firewall configuration matters
But setting up a firewall the right way isn't always easy. Create rules that are too strict, and your employees won't be able to complete important work. Conversely, if you make the rules too lax, you'll allow dangerous activity to happen right beneath your nose.
Understanding firewall limitations
A firewall isn't bulletproof either. Even hobby hackers understand how to get around simple firewalls so they can do as they please without impediment. Monitoring remains an important part of your work. If a breach happens, you can step in and stop it.
But a firewall is an important and basic part of offering safety and security to your company, no matter the threats that come your direction. It's smart to have one.
At Okta, we offer a trusted platform you can use to secure identity. Our tools allow you to offer both customers and staff an easy sign-in process and a secure experience.
We'd love to talk with you about our firewall component. Contact us today.
Frequently asked questions
What does a firewall actually do?
A firewall inspects all traffic entering and leaving your network, compares it against a set of rules you define, and either allows or blocks it accordingly. It acts as a barrier between your internal systems and external threats.
What are the different types of firewalls available?
There are 10 main types, including packet filters, stateful inspection, next-generation firewalls, unified threat management, web application proxies, endpoint firewalls, virtual firewalls, connection tracking, application layer 7, and network address translation (NAT) solutions.
Can a firewall protect both servers and clients?
Yes. A firewall can block unauthorized access attempts targeting your servers and can also prevent clients within your network from downloading malicious files or connecting to harmful sources.
Is a firewall enough to fully secure my network?
No firewall is completely foolproof. Determined attackers can find ways around basic firewalls, which is why ongoing monitoring is essential. A firewall is a foundational layer of security, not a complete solution on its own.
What happens if firewall rules are configured incorrectly?
Rules that are too strict can prevent employees from completing legitimate work, while rules that are too permissive may allow dangerous activity to go undetected. Proper configuration is critical to balancing security and productivity.
What is a web application firewall?
When a firewall is deployed specifically to protect external-facing applications, it is referred to as a web application firewall. It governs traffic rules for a specific application rather than the entire network.
References
How Many Firewalls Do You Need? (March 2009). TechTarget.
94 Percent of Organizations See Firewalls as Critical Infrastructure. (August 2018). eWeek.
How to Get Around Your School or Workplace Firewall. (November 2019). Help Desk Geek.
