Level 2 · Access Control
AC.L2-3.1.20
External Connections
An external connection needs identified use, verification, and enforceable limits.
Official reference
The requirement
Verify and control/limit connections to and use of external systems.
DoD CMMC Assessment Guide, Level 2, version 2.13. AC.L2-3.1.20; requirement and objectives, printed page 58 ↗
Assessment objectives
What must be established
Determine if each applicable objective is satisfied. The labels below follow the cited DoD assessment guide.
- [a]
connections to external systems are identified;
- [b]
the use of external systems is identified;
- [c]
connections to external systems are verified;
- [d]
the use of external systems is verified;
- [e]
connections to external systems are controlled/limited; and
- [f]
the use of external systems is controlled/limited.
MET requires evidence that all applicable objectives are satisfied. Final, approved evidence is needed. A NOT APPLICABLE determination needs a scope-based basis and is equivalent to MET for scoring. Enduring exceptions and temporary deficiencies have specific conditions under 32 CFR 170.24; they are not a general permission to defer implementation.
Included Level 1 coverage · FCI
AC.L1-b.1.iii: External Connections
Connections to external systems need identified uses, verification, and enforceable limits.
Level 2 includes Level 1 safeguarding coverage. This is the FAR-based Level 1 assessment context mapped into the 110-requirement library, not an additional Level 2 requirement.
Verify and control/limit connections to and use of external information systems.
DoD CMMC Assessment Guide, Level 1: AC.L1-b.1.iii; requirement and objectives, printed page 17 ↗
Level 1 assessment objectives and guidance
Determine if:
- [a]
connections to external systems are identified;
- [b]
the use of external systems is identified;
- [c]
connections to external systems are verified;
- [d]
the use of external systems is verified;
- [e]
connections to external systems are controlled/limited; and
- [f]
the use of external systems is controlled/limited.
Follow FCI to supplier services, personal systems, and other external connections. A list of vendors is useful only when it connects to the actual permitted systems and uses.
Examine
Inspect external-system inventories, connection approvals, verification records, and restrictions.
Interview
How is a new external service evaluated before staff use it for FCI?
Demonstrate or test
Trace an approved external connection from its recorded purpose to the setting or procedure that limits its use.
Level 1 evidence gaps
- Staff use an approved product through unapproved personal accounts.
- The inventory does not describe the connection or permitted use.
Level 1 has no weighted deduction. All applicable requirements must be fully implemented; the self-assessment is MET or NOT MET in its entirety.
Level 1 does not permit a POA&M. CAP P.11 addresses Level 2 certification planning, not a mandatory on-site rule for Level 1 self-assessments. Choose evidence and observations adequate to evaluate the actual physical environment and applicable objectives.
- DoD CMMC Assessment Guide, Level 1 ↗AC.L1-b.1.iii; requirement and objectives, printed page 17
- 32 CFR 170.24: Assessment findings and scoring ↗170.24(b) and (c)(1)
- 32 CFR 170.21: POA&M eligibility and closeout ↗170.21(a)(1) and (b)
- FAR 52.204-21: Basic safeguarding ↗52.204-21(b)(1)(iii)
GAVII Cybersecurity assessment approach
Connect the objective to the evidence
Include supplier systems, personal systems, hosted services, and other external systems relevant to the scope. A contract with a provider does not replace technical and operational connection controls.
Assessment focus: objectives [a], [b], [c], [d], [e], [f]. Use the methods together; a single example does not establish every objective.
Examine
Compare the external-system inventory, approved uses, verification records, and network or application restrictions.
Interview
How do you verify a proposed external connection and decide which uses are permitted?
Demonstrate or test
Trace one external integration from approval through its configured permissions and monitoring or restriction mechanism.
Evidence gaps to look for
- A vendor list is offered without connection details.
- A permitted service can be used through unapproved accounts or devices.
GAVII Cybersecurity’s examples illustrate ways to examine, interview, and test. They are not a mandatory artifact list or a guarantee of an assessment result. Combine methods and address every applicable objective in the actual scope.
Assessment constraints
Scoring and POA&M eligibility
Score: 1
If this requirement is NOT MET, deduct 1 point from the Level 2 maximum of 110. The deduction applies to the requirement, not separately to each objective.
Scoring rule ↗POA&M: Not eligible
This requirement is explicitly excluded by 32 CFR 170.21(a)(2)(iii); it cannot be deferred on the POA&M used for Conditional Level 2 status.
POA&M rule ↗Conditional Level 2 requires a score of at least 88 out of 110 and satisfaction of every eligibility condition. A 1-point requirement is not automatically eligible. The permitted POA&M must be closed through the appropriate closeout assessment within 180 days of the Conditional CMMC Status Date. An operational remediation plan does not confer Conditional Status.
Assessment planning
Location and observation
Not specifically listed in CAP P.11
This requirement is not specifically listed in CAP P.11. That does not establish that remote assessment is sufficient: the Lead CCA and C3PAO determine an adequate approach for the actual scope and evidence.
CAP §P.11, pages 10–11 ↗Check the source
References and related requirements
- DoD CMMC Assessment Guide, Level 2 ↗AC.L2-3.1.20; requirement and objectives, printed page 58. 2.13, September 2024.
- 32 CFR 170.24: Assessment findings and scoring ↗170.24(b) and (c)(2). Current electronic Code of Federal Regulations.
- 32 CFR 170.21: POA&M eligibility and closeout ↗170.21(a)(2) and (b). Current electronic Code of Federal Regulations.
- NIST SP 800-171 Rev. 2 ↗Requirement 3.1.20. February 2020, updated January 2021.
- NIST SP 800-171A ↗Assessment procedure 3.1.20. June 2018.
- Cyber AB CMMC Assessment Process (CAP) ↗P.11, printed pages 10-11; Level 2 certification assessment-location planning. 2.0, December 2024.
Program timing and contract applicability can change independently of these requirements. Check current DoD program notices and your solicitation or contract before making a compliance decision. Open the official DoD resource hub.