Network Security 101: Choosing and Configuring the Right Firewall for Your Business

Your business firewall is the critical gatekeeper between your network and the internet—the first line of defence against cyber threats targeting Australian businesses. While cloud services have transformed how we think about network perimeters, most Sydney businesses still have on-premises resources requiring protection: servers, printers, phone systems, IoT devices, and network infrastructure. Understanding firewall security options helps you choose appropriate protection that matches your actual risk profile without overspending. In this guide, we explain how firewalls work, compare different types, and help you select the right solution for your SMB's cybersecurity needs.

What Is a Firewall and How Does It Work?

A firewall is a network security device—physical hardware or software—that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It establishes a barrier between your trusted internal network and untrusted external networks like the internet. When data packets attempt to enter or leave your network, the firewall examines them against its ruleset and either allows, blocks, or logs the traffic accordingly.

Key Firewall Functions

Modern business firewalls perform several security functions beyond simple traffic filtering:

Packet filtering: Examines individual packets and blocks those that do not meet security criteria based on IP addresses, ports, and protocols
Stateful inspection: Tracks active connections and makes decisions based on the context of the traffic, not just individual packets
Network Address Translation (NAT): Hides internal IP addresses from external networks, providing an additional layer of security
VPN termination: Provides secure encrypted tunnels for remote workers and site-to-site connectivity
Logging and reporting: Records traffic patterns and security events for analysis and compliance

Understanding Firewall Types

Business firewalls range from basic to enterprise-grade, with different capabilities and price points. Understanding these categories helps you match the solution to your needs:

Basic Router Firewalls

Your ISP-provided router includes a basic stateful firewall that blocks unsolicited incoming traffic using NAT. While this provides minimal protection, it offers no visibility into what is being blocked, no logging for security investigations, and no advanced threat detection. It is essentially free but inadequate for business use beyond the smallest home offices. The Australian Cyber Security Centre explicitly recommends dedicated firewall solutions rather than relying on ISP equipment.

Business-Grade Firewalls

Dedicated firewall appliances from vendors like Fortinet, SonicWall, or Cisco provide stateful packet inspection, VPN capabilities, centralised management interfaces, and detailed logging. These devices are purpose-built for security with dedicated processors and memory. They are suitable for businesses with on-premises servers, specific security requirements, or compliance obligations that mandate network segmentation and monitoring.

Unified Threat Management (UTM)

UTM appliances combine firewall functionality with additional security services in a single device: intrusion prevention systems (IPS), content filtering, gateway antivirus scanning, application control, and sometimes anti-spam. These all-in-one devices simplify security management for SMBs by consolidating multiple security functions, reducing complexity and the number of separate solutions to manage. Most Australian SMBs with 10-100 employees find UTM devices the optimal balance of capability and manageability.

Next-Generation Firewalls (NGFW)

NGFWs add application awareness, user identity integration, and advanced threat detection to traditional firewall capabilities. Unlike traditional firewalls that only understand ports and protocols, NGFWs can identify specific applications regardless of port—meaning you can block Dropbox while allowing OneDrive, or restrict Facebook while permitting LinkedIn. They integrate with directory services like Active Directory to apply policies based on user identity rather than just IP address. NGFWs typically include sandboxing capabilities to analyse suspicious files in isolated environments.

Does Your Business Need a Firewall?

The answer depends on your specific environment and what assets you need to protect. The ACSC recommends that organisations implement firewalls between their networks and public network infrastructure. Here is how to assess your requirements:

When You Definitely Need a Firewall

On-premises servers: File servers, application servers, databases, or domain controllers require network-level protection
VPN access requirements: Remote workers need secure encrypted access to internal resources
Compliance obligations: Industry regulations or frameworks like Essential Eight require network segmentation and monitoring
Multiple office locations: Site-to-site connectivity requires secure tunnels between locations
Guest WiFi networks: Visitor access must be isolated from your production network
IoT and OT devices: Smart devices, cameras, and operational technology require network segregation
PCI DSS requirements: If you process card payments, firewall controls are mandatory

When You Might Not Need a Traditional Firewall

Fully cloud-based operations with no on-premises infrastructure to protect
Small office with only laptops and phones accessing cloud services like Microsoft 365
Remote-first business with no central office or shared physical network

Even cloud-first businesses need network security—just delivered differently. If you do not have on-premises infrastructure, consider cloud-native security solutions like Microsoft Defender for Cloud Apps, Cloudflare Gateway, or Zscaler rather than traditional hardware firewalls.

Best Firewall Solutions for Australian SMBs

When selecting a business firewall, consider factors like your user count, required throughput, VPN needs, and whether you have internal IT expertise to manage it. Here are the leading options for Australian SMBs:

Fortinet FortiGate: The most popular SMB choice in Australia, offering excellent performance-to-price ratio with comprehensive UTM features. FortiGate integrates well with FortiClient endpoint protection and offers strong Australian support. Models range from the FortiGate 40F for small offices to the 100F for larger businesses.
SonicWall TZ Series: Established SMB firewall brand with over 30 years of history. Comprehensive security services, good VPN performance, and competitive pricing. The TZ270 and TZ370 suit most SMB requirements.
Cisco Meraki MX: Cloud-managed firewalls with simple deployment and excellent visibility through the Meraki dashboard. Subscription-based licensing includes all security features. Ideal for multi-site businesses wanting centralised management without on-premises expertise.
WatchGuard Firebox: User-friendly interface with Dimension visibility tool providing excellent traffic analytics. Strong in the SMB market with good channel support in Australia.
pfSense/OPNsense: Open-source firewall options running on standard hardware. Lower cost but require technical expertise to deploy and maintain. Good for businesses with IT staff who want granular control.
Sophos XGS: Strong integration with Sophos endpoint protection through Synchronized Security. Good for businesses already using Sophos antivirus.

Essential Firewall Configurations for Security

Proper configuration is as important as selecting the right hardware. The ACSC's Guidelines for Gateways provide detailed requirements. Here are the essential configurations for business firewall security:

Default deny policy: Block all traffic not explicitly permitted. Start with restrictive rules and open only what is documented as necessary. This is mandated by ACSC ISM controls.
Change default credentials immediately: Admin interfaces with default passwords are actively scanned by attackers. Use strong, unique passwords and enable multi-factor authentication where available.
Enable comprehensive logging: Without logs, you cannot investigate security incidents or understand traffic patterns. Retain logs for at least 90 days and consider a SIEM solution for analysis.
Keep firmware updated: Firewall vulnerabilities are high-value targets for attackers. Subscribe to vendor security advisories and patch promptly—ideally within 48 hours for critical vulnerabilities.
Implement network segmentation: Separate guest WiFi, IoT devices, development environments, and sensitive systems into different network zones with controlled traffic between them.
Review and audit rules regularly: Firewall rules accumulate over time as needs change. Audit and clean up unused or overly permissive rules quarterly. Document the business justification for each rule.
Configure security alerts: Set up notifications for suspicious activity, failed login attempts, and configuration changes. Route alerts to monitored email addresses or your SIEM.
Enable intrusion prevention: If your firewall supports IPS, enable it with regularly updated signatures to block known attack patterns.
Implement geo-blocking where appropriate: If your business only operates in Australia, consider blocking traffic from high-risk countries you never expect legitimate connections from.

Firewall Integration with Endpoint Security

Modern cybersecurity requires layered defences. Your firewall should work in concert with endpoint protection, email security, and identity management. Leading vendors offer synchronized security features where firewalls and endpoints share threat intelligence—if an endpoint detects malware, the firewall can automatically isolate that device from the network. For businesses using Microsoft 365, Azure AD Conditional Access policies can complement firewall rules by requiring compliant devices before granting network access.

Cloud-First Security Alternatives

For businesses without significant on-premises infrastructure, cloud-delivered security services may complement or replace traditional firewalls:

Microsoft 365 security features: Conditional Access policies, Defender for Cloud Apps, and Azure AD Identity Protection provide cloud-native access controls
DNS filtering: Cloud-based threat blocking services like Cisco Umbrella, Cloudflare Gateway, or DNSFilter block malicious domains before connections are established
Zero Trust Network Access (ZTNA): Solutions like Zscaler Private Access or Cloudflare Access replace traditional VPNs with identity-based access controls
Secure Access Service Edge (SASE): Comprehensive cloud-delivered network security combining SD-WAN with security services
Cloud-managed firewalls: Services like Cisco Meraki or Forcepoint offer hardware firewalls managed entirely through cloud dashboards

Common Firewall Security Mistakes

Even with good hardware, these configuration and management errors undermine your security:

Permitting "any-any" rules: Overly permissive rules that allow all traffic defeat the purpose of the firewall entirely
Ignoring outbound filtering: Many businesses focus only on inbound traffic while malware needs outbound connections to exfiltrate data
Disabled logging: Turning off logging to save storage means you cannot investigate breaches or demonstrate compliance
Stale firmware: Running outdated firmware with known vulnerabilities is like leaving your front door unlocked
No backup of configuration: If your firewall fails, can you restore the configuration or will you rebuild from scratch?
Single point of failure: Critical networks should have redundant firewalls with failover capability

Important: A firewall you do not understand or actively manage is worse than none—it creates false confidence. If you cannot maintain it properly with regular updates, log reviews, and rule audits, consider managed firewall services from a qualified MSP.

Firewall Costs for Australian SMBs

Budget appropriately for both hardware and ongoing subscription costs. Firewall security services like IPS signatures, URL filtering databases, and support contracts require annual renewals:

Entry-level (5-20 users): Hardware $500-1,500 AUD, annual subscriptions $300-600. Examples: FortiGate 40F, SonicWall TZ270
Mid-range (20-100 users): Hardware $1,500-5,000 AUD, annual subscriptions $600-1,500. Examples: FortiGate 60F/80F, Meraki MX67
Enterprise (100+ users): Hardware $5,000-15,000+ AUD, annual subscriptions $1,500-5,000+. Examples: FortiGate 100F, Meraki MX105
Managed firewall services: $200-800/month depending on complexity, includes monitoring, updates, and incident response

How We Researched This Article

This article was compiled using information from authoritative industry sources to ensure accuracy and relevance for Australian businesses.

Sources & References

•
ACSC Guidelines for Gateways (ISM)
Australian Cyber Security Centre official gateway and firewall guidelines
•
ACSC Security Considerations for Edge Devices
ACSC guidance on securing firewalls, routers, and network devices
•
NIST SP 800-41 Rev 1: Guidelines on Firewalls and Firewall Policy
US Government best practices for firewall policy and configuration
•
ACSC Essential Eight Maturity Model
Australian cybersecurity framework including network segmentation requirements

* Information is current as of the publication date. Cybersecurity guidelines and best practices evolve regularly. We recommend verifying current recommendations with the original sources.

Frequently Asked Questions

What is a business firewall and why do I need one?

A business firewall is a dedicated security device that monitors and controls all network traffic entering and leaving your organisation. Unlike home routers, business firewalls provide detailed logging, advanced threat detection, VPN capabilities, and granular control over applications and users. You need one if you have on-premises servers, compliance requirements, or need secure remote access for employees.

How much should an Australian SMB spend on a firewall?

Entry-level business firewalls start around $500-1,500 AUD for hardware plus $300-600 per year for security subscriptions covering threat updates. Mid-range UTM appliances suitable for 20-100 users typically run $1,500-5,000 for hardware. Balance cost against your actual needs—do not overbuy enterprise features you will never use, but do not rely on consumer-grade equipment for business.

Can a firewall stop ransomware attacks?

Firewalls with advanced threat protection and sandboxing can block some ransomware at the network level, but they are not sufficient alone. Ransomware commonly enters via phishing emails, compromised credentials, or vulnerable endpoints—paths that may bypass traditional firewall inspection. Defence in depth with endpoint protection, email security, and user training is essential.

Do we need both a firewall and endpoint protection software?

Yes, absolutely. Firewalls protect network boundaries and monitor traffic between zones. Endpoint protection (antivirus and EDR) protects individual devices like laptops and desktops. With remote work and cloud services, devices frequently operate outside your office firewall. Both layers are essential for comprehensive protection.

Should we manage our firewall internally or use managed services?

Unless you have dedicated security expertise on staff, managed firewall services typically make sense for SMBs. Firewall misconfigurations are common and can be dangerous—creating security gaps or blocking legitimate business traffic. Managed services ensure proper setup, continuous monitoring, timely updates, and rapid incident response for roughly $200-500 per month.

What is the difference between UTM and NGFW firewalls?

UTM (Unified Threat Management) devices combine multiple security functions in one appliance: firewall, IPS, antivirus, content filtering, and VPN. NGFWs (Next-Generation Firewalls) add application-level awareness and user identity integration to traditional firewall features. In practice, modern SMB devices blend both categories. For most Australian SMBs, the distinction matters less than selecting appropriate features for your specific needs.