Firewall
A network security system that monitors and controls incoming and outgoing traffic based on predefined rules, acting as a barrier between trusted and untrusted networks.
A firewall is like a security guard for your network. It sits between your internal network (computers, servers, devices) and the outside internet, inspecting all traffic that passes through and blocking anything that does not meet your security rules.
Types of Firewalls
- Software firewalls — built into your operating system (Windows Firewall, macOS firewall) or installed as an app; protects individual devices
- Hardware firewalls — dedicated physical devices placed between your network and internet connection; protects the entire network
- Cloud firewalls — managed services that filter traffic before it reaches your network; increasingly popular for businesses with remote workers
- Next-generation firewalls (NGFW) — combine traditional filtering with advanced features like intrusion detection and application awareness
For Malaysian SMEs
Even the smallest business should have at least a properly configured router firewall and software firewall on each device. For businesses handling customer data under PDPA, a dedicated firewall solution demonstrates the "practical steps" required by the Act to protect personal data.
Best Practices
- Enable your operating system's built-in firewall — it is free and effective for basic protection
- Configure rules to block all incoming traffic by default, only allowing what is needed
- Regularly review and update firewall rules as your business needs change
- Log firewall events for incident investigation
- Consider a managed firewall service if you lack in-house IT expertise