Firewall and network protection: the backbone of cybersecurity

What is a firewall?

A firewall acts as a security guard for your business, controlling incoming and outgoing network traffic based on predefined security rules, and using security subscriptions to identify malicious threats trying to access your network. It does this by analysing the traffic in real-time. Firewalls can block or allow traffic and quarantine suspicious threats or users. It’s a multi-layered security system that helps prevent cyberattacks, safeguards data and ensures business continuity.

Firewalls have been around since the late 1980s and have become indispensable for modern businesses to prevent unauthorised access, stop malware, and maintain the integrity of sensitive information. They form a key part of any robust firewall and network protection strategy.

Key security features of business firewalls

These are some key security features available in modern firewalls that help keep businesses secure:

• Antivirus & Malware Protection: Modern firewalls include built-in antivirus scanning to detect and block malicious files before they can spread. This adds an extra layer of defence against ransomware, trojans and other malware threats.
• Intrusion Prevention System (IPS): IPS actively monitors network traffic for suspicious activity and blocks attacks in real time. This helps protect against threats like brute-force attacks, exploits and unauthorised access attempts.
• Web Filtering & Content Control: Businesses can control what websites employees can access by blocking malicious or inappropriate content. This improves productivity, reduces security risks and prevents employees from accidentally visiting phishing sites.
• SSL Inspection (Deep Packet Inspection): Many threats hide inside encrypted traffic. SSL/TLS inspection allows firewalls to scan encrypted data for hidden malware and suspicious activity without compromising security.
• High Availability (HA) & Redundancy: For businesses that can’t afford downtime, HA firewalls ensure continuous protection by automatically switching to a backup unit if the primary one fails. This guarantees network security and reliability even during hardware failures.
• Vendor Support & Regular Updates: Cyber threats evolve daily, so firewalls need constant updates to stay effective. Business-grade firewalls come with vendor support, firmware updates and threat intelligence to keep security measures up to date.

Different types of firewall delivery methods

There are several types of firewall delivery methods, each suited to specific environments:

• Hardware firewalls: Physical devices installed between your network and the internet. These self-contained appliances are ideal for medium and large organisations looking to protect many devices.
• Software firewalls: Applications running on individual devices, providing user-level security. They consume some of the host device’s CPU and RAM resources but provide a fine-grained level of control and significant protection to the devices on which they are installed.
• Cloud-based firewalls: Also known as Firewall-as-a-Service or FWaaS, these are scalable, remote solutions managed in the cloud, ideal for distributed networks with remote work devices and companies with small tech teams. They offer optimised protection for SaaS applications and centralised management for IT administrators.

Best practices for configuring firewall rules

Effective firewall and network protection relies on well-configured rules. These rules govern how traffic flows in and out of your network, ensuring only legitimate data packets pass through.

Follow the principle of least privilege

• When creating firewall rules, only allow necessary traffic between specific sources and destinations.
• Instead of using "any" for source or destination, define only the required IPs, subnets, or services.
• Avoid overly broad rules that expose your network to unnecessary risks.

Conduct external penetration testing after major changes

• After any major network change, perform an external penetration test to ensure no new vulnerabilities have been introduced.
• Engage a trusted security firm or use automated vulnerability scanners to check for open ports and misconfigurations.

Enable logging for critical rules

• Enable detailed logging on important rules to monitor and detect unusual activity.
• Store logs in a centralised system (SIEM, syslog server, or cloud logging solution) for easier analysis.

Regularly review and clean up firewall rules

• Over time, old rules may become obsolete or introduce risks, so you should review them at least quarterly.
• Remove any unused, redundant, or overly permissive rules that could be exploited.

To create the most effective firewall rules,  preparation and prevention are essential.