Installing a firewall is one of the most impactful security steps any organization can take. Here’s a practical guide to getting started.
Why a Firewall is Non-Negotiable
Any system connected to the Internet without a firewall will be probed by automated scanners within minutes. These scanners are looking for open ports, known vulnerabilities, and default credentials. A firewall stops the vast majority of this traffic before it reaches your systems.
Choosing the Right Firewall
For most small and medium businesses, a UTM (Unified Threat Management) appliance is the best choice. These devices combine firewall, VPN, IPS, antivirus, and web filtering in a single box at an affordable price. Leading options include SonicWALL TZ series, Fortinet FortiGate, Watchguard Firebox, and Cisco ASA.
First Steps After Installation
- Change all default passwords immediately
- Disable all management access from the Internet
- Enable logging and ensure logs are being retained
- Start with a deny-all policy and add rules only as needed
- Document every rule you add and its business justification