How to Read Firewall Rules & Why Default Deny Matters in OT | OT Security Module 5.5

An "allow any" rule left over from a troubleshooting session two years ago is still one of the most common critical findings in OT security assessments today. Being able to read a firewall rule set is a practical OT security skill. In this lesson, we break down the six components of every firewall rule, walk through a real example rule set for protecting PLCs from SCADA servers, and explain why default deny is the correct failure mode for OT environments. By the end of this video, you'll be able to read and evaluate a firewall rule set, and you'll know how to maintain rule sets over time so stale allow-any rules don't accumulate. 🕐 Chapters: 0:00 – The six components of a firewall rule 2:00 – Reading a sample OT rule set 3:30 – Default deny vs. default allow: which failure mode do you want? 5:00 – Rule set maintenance and review cadence 6:00 – Key takeaways and what's coming next (common firewall misconfigurations) Part of Module 5: Firewalls Full course playlist: [link] If this was useful, subscribe for more content like this. #OTSecurity #IndustrialCybersecurity #ICS #SCADA #FirewallRules #DefaultDeny