Firewall Documentation Blueprint
A template and process for documenting your firewall setup — rules, VLANs, objects, and change history — so anyone can understand and maintain it.
Difficulty
Beginner
Estimated time
1–2 hours
Tags
What this helps with
- ✓Creating a living network diagram
- ✓Documenting firewall rules in plain language
- ✓Tracking change history
- ✓Onboarding new team members
- ✓Preparing for audits
Step-by-step plan
- 1
Draw your network topology
Use draw.io or Excalidraw. Include all VLANs, physical segments, upstream connections, and key hosts. Export as SVG and PDF.
- 2
Document VLAN and subnet table
Spreadsheet with columns: VLAN ID, Name, Subnet, Gateway, Purpose, Who can access it, Internet access (Y/N).
- 3
Document all firewall rules
Export rules from OPNsense as CSV or copy manually. For each rule: source, destination, port, protocol, reason/ticket reference.
- 4
Set up a change log
Create a simple Markdown file or Notion page. Every change: date, who, what, why. Link to the relevant ticket or discussion.
- 5
Review and share
Store documentation in a shared location (Git, Notion, SharePoint). Schedule a quarterly review to keep it current.
Download this blueprint
Network Documentation Template (PDF)