The best firewall for small business in 2025 is the Fortinet FortiGate 40F, offering enterprise-grade threat protection, VPN support, and intrusion prevention at under 500 pounds. You get hardware-level security that blocks 99.7% of known threats without slowing your network or requiring a dedicated IT team to manage it.
What Is a Firewall and Why Your Small Business Needs One
A firewall monitors all incoming and outgoing network traffic and blocks unauthorised connections based on security rules. It sits between your internal network and the internet, inspecting every data packet before it reaches your devices. Without one, your business is exposed to malware, ransomware, and data exfiltration. Our guide on what a firewall is and how it blocks attacks covers the fundamentals.
Hardware Firewalls vs Software Firewalls: Key Differences
Hardware firewalls are physical appliances that protect your entire network at the perimeter. They process traffic using dedicated processors, meaning zero performance impact on individual workstations. Software firewalls run on existing computers and protect individual devices rather than the whole network.
For most small businesses with 5 to 50 employees, a hardware firewall provides the best protection. It covers every device on the network, including printers, IP phones, and IoT sensors that cannot run software firewalls themselves. If your budget is tight, pairing a router with built-in firewall capabilities with host-based software firewalls gives you layered defence at a lower cost.
Best Firewalls for Small Business: Ranking Table
| Firewall | Type | Throughput | VPN Support | Price (GBP) | Best For |
|---|---|---|---|---|---|
| Fortinet FortiGate 40F | Hardware | 5 Gbps | Yes (IPsec/SSL) | 380 | Overall best for SMBs |
| WatchGuard Firebox T25 | Hardware | 3.4 Gbps | Yes (IPsec/SSL) | 450 | Ease of management |
| SonicWall TZ270 | Hardware | 2 Gbps | Yes (IPsec/SSL) | 420 | Retail and hospitality |
| pfSense Plus | Software | Varies by hardware | Yes (OpenVPN/WireGuard) | Free (hardware separate) | Budget-conscious teams |
| Ubiquiti UniFi Dream Machine Pro | Hardware | 3.5 Gbps | Yes (L2TP/WireGuard) | 340 | Unified network management |
How to Choose the Right Firewall for Your Business
Assess Your Network Size and Traffic Volume
Count your network devices and estimate peak bandwidth usage. A business running 10 workstations, a file server, and VoIP phones needs at least 1 Gbps firewall throughput. An undersized appliance creates a bottleneck that slows every connection.
Evaluate Threat Protection Features
Look for intrusion prevention (IPS), antivirus scanning, application control, and web filtering. The FortiGate 40F and SonicWall TZ270 include all four in their base licence. WatchGuard bundles them in the Total Security Suite add-on. Pair your firewall deployment with a regular network hardening routine to close gaps the firewall alone cannot cover.
Factor in Total Cost of Ownership
Hardware cost is only the starting point. Annual subscriptions for threat intelligence, content filtering, and support typically add 150 to 400 pounds per year. pfSense eliminates licence fees but requires more technical skill to configure.
Firewall Configuration Best Practices for Small Business
Start with a deny-all default policy and create allow rules only for traffic your business requires. Segment your network into zones: employee workstations, guest WiFi, servers, and IoT devices. Apply strict rules between zones so a compromised printer cannot reach your accounting server. Enable logging and review logs weekly to catch unusual patterns early.
Frequently Asked Questions
Do I need both a hardware and software firewall?
Yes. A hardware firewall protects your network perimeter, while software firewalls on individual devices block threats that bypass the perimeter or originate internally. This layered approach, called defence in depth, significantly reduces your attack surface.
How often should I update my firewall firmware?
Check for firmware updates monthly and apply critical security patches within 48 hours of release. Outdated firmware is one of the top three causes of firewall compromise in small business environments, according to the 2025 Verizon Data Breach Investigations Report.
Can a firewall replace antivirus software?
No. A firewall controls network traffic at the perimeter, but it cannot detect malware already on a device or scan files downloaded through encrypted connections. You need endpoint antivirus alongside your firewall for complete protection.