Packet Filtering Firewalls: How They Work & Where They Fall Short | OT Security Module 5.2

The oldest firewall technology still guarding OT networks today reads nothing more than a packet's header — no idea what's inside, no memory of what came before it. This lesson covers packet filtering firewalls — the simplest and oldest form of firewall technology. We explain how packet filtering evaluates traffic using only header fields (source IP, destination IP, ports, protocol), why it's stateless, and where its limitations create security gaps in OT environments. By the end of this video, you'll know exactly where packet filtering still appears in OT infrastructure — including Cisco ACLs and embedded industrial routers — and why it isn't enough on its own. 🕐 Chapters: 0:00 – How packet filtering works 1:30 – Advantages: speed, simplicity, broad hardware support 3:00 – Limitations: stateless evaluation and payload blindness 4:30 – Where you'll find packet filtering in OT environments 5:10 – Key takeaways and what's coming next (stateful inspection) Part of Module 5: Firewalls Full course playlist: [link] If this was useful, subscribe for more content like this. #OTSecurity #IndustrialCybersecurity #ICS #SCADA #PacketFiltering #NetworkSecurity