The Toughest 1-Point Control in NIST 800-171

Control 3.1.20 is worth 1 point out of 110 in NIST 800-171, and it almost stalled our assessment cold. We had CUI scoped and our boundary defined. What tripped us was one word: external. Does it mean every website on earth, or just the systems that actually handle CUI? In this video I walk through a real client engagement prepping for CMMC compliance, how a well-defined scope still got stuck on 3.1.20, why the literal reading of external systems blows up your assessment scope, and how we narrowed it to the cloud portals and file transfer sites that actually touch controlled unclassified information. This isn't a technical fix. It's a business decision. You define as a company which external systems are in scope for this control based on how your people actually handle CUI, and there's no POA&M deferral on this one. If you hold government contracts or support the defense industrial base, and you're working through cybersecurity compliance for CMMC, start here before the assessor has to ask. I'm John Barker, independent fractional CIO with no tools to sell and no commissions. Be the titan over your tech. Chapters 00:00 - One point that sets your scope 00:22 - The setup: boundary was done 00:50 - The every-website trap 01:25 - Anchoring external to CUI workflows 02:00 - What most templates miss 02:25 - Define it as a company --- Independent fractional CIO for owners of $5M to $50M businesses. Technology and cybersecurity strategy, with no tools to sell, no commissions, and no conflict. New here? What a fractional CIO does, in a few minutes:    • What Does a Fractional CIO Do? | 2:17 over...   Work with me: https://titanof.tech Connect: LinkedIn →   / johnbarker78