Firewall rule design and review
Write least-privilege rules, predict what a first-match policy does, find shadowed and risky rules, and run rule changes safely.
- Level
- Intermediate
- Length
- About 50 minutes
- Contents
- 3 lessons · 1 video · final exam
- Status
- Published · updated 1 Oct 2026
Skills you'll practise
- Predict the outcome of a packet against a first-match rule list
- Find shadowed, redundant, over-broad and stale rules
- Write a least-privilege rule with source, destination, service and justification
- Run a rule change with review, testing, rollback and documentation
Course outline
- 1.Designing and reviewing firewall rulesVideo · 2 min
- 2.How rule lists are evaluatedLesson · 20 min
- 3.Designing and changing rules safelyLesson · 20 min
- 4.Zones, segmentation and egress filteringLesson · 20 min
- 5.Firewall rule design and review: knowledge checkKnowledge check · 20 questions
- 6.Firewall rule design and review: practical exerciseKnowledge check · 1 question
- 7.Final exam7 questions · passing it completes the course, so people who already know the material can test out
Sources it draws on
The lessons and questions are written from these references, so learners can go back to the original.
- NIST SP 800-41 Rev. 1: Guidelines on Firewalls and Firewall Policy
- CIS Controls v8: Control 4 and Control 13 (secure configuration, network monitoring and defense)
- RFC 1918: Address Allocation for Private Internets
See it with your own jobs and topics
Tell us about your team and we'll walk you through setup, from choosing jobs to your first skills check.