How Does Firewall Software Work?
To understand how firewalls work, it’s first important to clarify what a packet is. As soon as data is transmitted wirelessly, it’s broken down into manageable chunks called packets.
Each packet is made up of these components:
- A header with its destination, and instructions how to re-assemble
- The body of data being transferred
Firewalls sit between the sender and receiver – a format called a reverse proxy – and examine each packet being sent or requested. This insight lets network admins define precisely which traffic they want in their network. From the backend, admins achieve this through rules.
How Firewall Rule Works
When data packets reach the firewall, it evaluates them against the rules to determine if the packets meet the conditions for safe and authorized access. Many of today’s firewalls are shipped with pre-configured rules that cut off many common attack paths.
Admins can then tweak and add their own rules on top of this.
Note that firewalls run through rule lists in a top-to-bottom way, and they process custom rules first. This means, for firewall management, it’s key to review and remove old ones, or else it will slow down the valid connections.
Real-Life Example:
Let’s say admins want to stop a server from receiving or sending any data via port 22 – which cuts off many attacks relying on Secure Shell. They simply establish the rule in the firewall’s configuration, and from there, the firewall examines whether the destination of any new packets matches that.
If it does, the connection is simply dropped before data is sent or received.
But What About Encryption?
The online world has changed a lot since firewalls first became popular in the 90s. Today, most websites use HTTPS instead of unencrypted HTTP, so data packets are usually encrypted. VPNs also send data through secure, encrypted tunnels.
Modern firewalls like Check Point Quantum use a method called Deep Packet Inspection to handle this.
- They temporarily decrypt data to inspect its contents
- Then re-encrypt it before sending it on
This process requires powerful hardware, and systems like Check Point help maintain fast performance by skipping decryption when the CPU is very busy. Unlike traditional firewalls that checked if a packet matched preset rules, Next-Gen Firewalls (NGFW) analyze information from every packet to improve network traffic analysis.
Firewall Software Features
Here are the firewall features to be on a lookout for:
Behavioral Analysis
Since every connection on a network is logged via the firewall, an AI algorithm is able to build an image of normal activity. This helps to timely spot any unusual activities, like:
- If a user’s device tries to initiate connections to a strange server
- The firewall can identify the behavior as high-risk, and block it
Even more cutting-edge AI applications include the use of Large Language Models (LLMs). These assess the legitimacy of websites for:
- Phishing pages that pretend to be banking logins
- Inappropriate sites that could host pirated or drive-by malware
This is deepened by a provider’s threat intelligence, helping against zero-day and rule-evading attacks.
DNS Protection
DNS architecture is what links an IP address to its corresponding domain name.
Firewalls used to struggle to protect this piece of architecture, but modern firewalls include granular security configurations, like the ability to:
- Whitelist trusted servers
- Encrypt DNS queries
Inspection and Protection of Encrypted Traffic
NGFWs allow for secure HTTPS traffic to be inspected while still protecting performance, and are applicable across all forms of traffic encryption, like:
Data Center Agility
Because NGFWs can be deployed via virtual firewall, they’re able to be ramped up very quickly.
This makes them able to support dynamic, high-speed environments like data centers and cloud-provisioned resources. Plus, policies can be automatically applied across newly deployed virtual machines.
Customizability and In-Depth Reporting
NGFWs’ customizability allows you to tailor configurations to your specific needs, such as:
- Creating rules for unique traffic patterns
- Adapting to compliance requirements like GDPR
Reports can then be generated to a predefined schedule, with specific focal points that are most relevant.
Hardware Firewall vs. Software Firewall
Firewall adaptability means that it can be deployed both as a physical piece of equipment, or as software. Choosing the correct type can offer a wealth of benefits to your organization.
Hardware Firewall
As a physical device, hardware firewalls are linked to their corresponding server stacks and have their own inbuilt CPU, which defines the throughput they are capable of achieving. Hardware firewalls are particularly useful for efficient routing, as they decide which network path is most efficient for each packet.
Software Firewall
Software firewalls run on the host. This grants them the ability to assess the device’s own application-level access in a more granular way. At the same time, this visibility also lets them be tightly integrated with other security tools, like Endpoint Detection and Response (EDR).
This approach can dig deeper into an endpoint’s own activity, while offering a rich data source for threat analysis.
What Firewall is Best for You?
Choosing the right firewall is critical to achieving optimum, long-term protection.
That’s why we put together a NGFW buyers’ guide, which pinpoints the specific features your potential firewall needs to target. Check Point Quantum delivers comprehensive security by combining NGFW features like AI-driven threat prevention and efficient encrypted traffic inspection with tried-and-tested rulesets.
Quantum provides immediate security and routing capabilities, allowing efficient traffic management and segmentation, while leveraging NAT to secure internal networks and optimize IP usage.
Explore how it works with a demo.
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