NetworkTigers discussed the versatility and importance of firewalls.
Despite being one of the oldest cybersecurity tools available, firewalls remain essential components of network protection. At first designed for the single purpose of preventing access to a network from anyone without authorized permission, firewalls have kept up with network evolution by adding features that have allowed them to remain on the front lines for decades. Since the advent of networking, firewalls have been both ubiquitous and integral.
As a result, even the greenest network administrator will know the basics of firewall functionality. Several key concepts underpin robust firewall implementation. It is important to understand the variety of features available in modern firewalls to ensure you choose the firewall solution best suits your needs.
What is a firewall?
A firewall is a cybersecurity component that acts as a screener for incoming and outgoing traffic. Depending on its configuration, it can block access from accounts that do not meet the requirements for entry by taking a look at the data packets moving through it. Firewalls can also monitor network traffic and provide information and statistics that can be used to assess system health and flag potentially malicious activity.
In the past, firewalls have exclusively come in the form of hardware. However, firewalls can now also come as software applications.
Firewalls can be stateful or stateless and come in traditional and next-generation models.
Stateful vs. stateless firewalls
Stateful firewalls deeply inspect data packet contents and the characteristics of the information included. These firewalls look into the behavior of data packets to both catalog patterns and block anything determined to be suspicious or potentially malicious.
Stateful firewalls are reasonable solutions for small businesses or individuals who want to up their security without spending much time getting into the weeds setting up parameters and customizing their protocols. Stateful firewalls also can make filtering decisions based on past traffic data.
However, stateful firewalls can be fooled by savvy attackers, especially if they aren’t diligently updated with security patches from the manufacturer.
Stateless firewalls require more configuration from a network administrator. Instead of thoroughly inspecting the contents of a packet, a stateless firewall looks at a packet’s destination and source to determine whether or not it is given a pass. The rules it follows remain static, creating a rigid line of security. They can process more traffic more efficiently than a stateful firewall.
Stateless firewalls are better suited to large enterprise networks undergoing consistent maintenance. Because they demand customization to work correctly, they are best implemented by experienced administrators with a deep knowledge of how communication within their network is supposed to function.
Traditional vs. next-generation firewalls
Traditional firewalls offer basic, stateful network traffic inspection as it moves into and out of your system.
Next-generation firewalls (NGFWs) are fully loaded with features such as integrated intrusion protection and application awareness that allow them to make decisions regarding their treatment of traffic. NGFWs can process higher traffic than traditional firewalls. If connected to a network or database, they can receive updates regarding current threats to detect malicious behavior that may not have been flagged.
Firewall features and capabilities
Network traffic filtering
The primary function of a firewall is to protect your network from unauthorized access. By configuring a firewall to your specifications, you can determine what requirements must be met for a user to be allowed through. Those who do not meet expectations are then barred from entry, thus protecting your system from malicious intent or accidental exposure.
In this way, a firewall acts as a filter through which only traffic with permission can pass.
Intrusion detection and prevention
If suspicious activity is observed, a properly configured firewall with intrusion detection systems (IDS) and intrusion prevention systems (ISP) can block and flag it.
While an IDS traditionally functions as a standalone security component, the lines between different devices and protocols can be blurry. Security firm Check Point explains that “many next-generation firewalls (NGFWs) have integrated IDS/IPS functionality. This enables them to both enforce the predefined filtering rules (firewalls) and detect and respond to more sophisticated cyber threats (IDS/IPS).”
Network address translation
A firewall equipped with Network Address Translation (NAT) consolidates the IP addresses of the devices connected to your network to just one associated with your router. Keeping the individual IPs of your endpoints private makes it much more challenging for an attacker to target a specific part of your architecture.
NAT firewalls are typically built into routers already, so manual configuration is usually unnecessary.
Application layer security
A firewall with application layer security can go beyond just protecting your network from outside intrusion. Using deep packet inspection (DPI), an application layer firewall can be configured to determine whether to block or allow activity to or from an app within the network.
Even if an intruder enters your system, an application layer firewall can shut down its attack if it detects unusual communication from a compromised app.
Data logging and monitoring
Firewalls can provide an indispensable look into your network’s traffic via logs that chart out system behavior, instances of rule violations, and any security events.
By closely examining their network’s operations, IT administrators can glean valuable data that can be applied not only to decisions regarding security best practices but also to those that have to do with efficiency and resource allocation.
Network segmentation is creating separate zones within your network, each with its own lines of defense. By segmenting your network, you can prevent intruders from moving within your system by locking them into only the segment they have penetrated.
Firewalls between network segments form the security perimeter that makes this protocol so effective. By configuring firewalls throughout your network, you can keep a threat actor from traveling laterally within your architecture and greatly minimize the damage a successful intrusion may result in.
Firewalls are essential for organizations or government agencies to maintain compliance with data security regulations. From protecting customer credit card data to ensuring the confidentiality of healthcare information, implementing strict firewall policies can prevent cyberattackers from stealing sensitive data and keep employees from accidentally stumbling into network areas that are meant to be secret.
Adhering to regulations is not only good practice but can also prevent your business from being sued in the event of a data breach.
Additionally, firewalls can be used to prevent internal employees from accessing predetermined websites or apps. This can keep workers from visiting sites that use too much bandwidth or pose potential security risks to the network.
Purchasing or upgrading your firewall
With so many options, it can be overwhelming when the time comes to purchase your first firewall or update one that may have fallen behind on features or manufacturer support.
Thankfully, you can find a vast selection of refurbished firewalls online. Many of these units still carry warranties passed from large companies that have undergone updates or network rebuilds.
Refurbished network equipment offers a great way to keep your system humming with modern demands while staying under budget.