AC.L2-3.1.20 — Verify and limit external system connections
Verify and control/limit connections to and use of external systems.
Verbatim NIST SP 800-171 Rev 2 requirement text (3.1.20).
How it's scored
1 point deducted from your SPRS score if unmet.
AC.L2-3.1.20 can never sit on a POA&M, regardless of your score: it is one of the six requirements 32 CFR 170.21(a)(2) excludes from Plans of Action & Milestones at conditional certification. It must be fully implemented before a Level 2 assessment can succeed.
What an assessor checks: the 6 assessment objectives
NIST SP 800-171A determination statements, verbatim. A CMMC Level 2 assessor marks AC.L2-3.1.20 MET only when every applicable objective is satisfied — and examines evidence, not assertions.
| Objective | Determination statement |
|---|---|
| 3.1.20[a] | connections to external systems are identified. |
| 3.1.20[b] | use of external systems is identified. |
| 3.1.20[c] | connections to external systems are verified. |
| 3.1.20[d] | use of external systems is verified. |
| 3.1.20[e] | connections to external systems are controlled/limited. |
| 3.1.20[f] | use of external systems is controlled/limited. |
Where do you stand on AC.L2-3.1.20?
The free Muster Score walks all 110 requirements — including every objective above — and computes your exact SPRS score in your browser. No signup, no upload, and your answers never leave your device.
Get your free Muster Score →Requirement and objective text: NIST SP 800-171 Rev 2 / SP 800-171A (verbatim). Scoring: DoD Assessment Methodology v1.2.1; POA&M eligibility: 32 CFR 170.21. Muster is independent and not affiliated with the U.S. Department of Defense or the Cyber AB; this page is compliance information, not legal advice or a certification.