Level 2 · System and Communications Protection
SC.L2-3.13.5
Public-Access System Separation
Public-facing components need physical or logical separation from internal networks.
Official reference
The requirement
Implement subnetworks for publicly accessible system components that are physically or logically separated from internal networks.
DoD CMMC Assessment Guide, Level 2, version 2.13. SC.L2-3.13.5; requirement and objectives, printed page 221 ↗
Assessment objectives
What must be established
Determine if each applicable objective is satisfied. The labels below follow the cited DoD assessment guide.
- [a]
publicly accessible system components are identified; and
- [b]
subnetworks for publicly accessible system components are physically or logically separated from internal networks.
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
SC.L1-b.1.xi: Public-Access System Separation
Public-facing system components need separation from internal networks.
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.
Implement subnetworks for publicly accessible system components that are physically or logically separated from internal networks.
DoD CMMC Assessment Guide, Level 1: SC.L1-b.1.xi; requirement and objectives, printed page 37 ↗
Level 1 assessment objectives and guidance
Determine if:
- [a]
publicly accessible system components are identified; and
- [b]
subnetworks for publicly accessible system components are physically or logically separated from internal networks.
Identify the publicly accessible components in the covered system. If there are none, record the basis for that applicability decision rather than assuming every organization needs to create a public-facing subnet.
Examine
Review public-service inventories, network segmentation, and allowed connectivity.
Interview
What prevents a public-facing service from reaching internal systems beyond its permitted connections?
Demonstrate or test
Inspect the implemented separation and use safe tests to demonstrate allowed and denied paths.
Level 1 evidence gaps
- A public service shares unrestricted internal access.
- An applicability claim overlooks an exposed component.
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 ↗SC.L1-b.1.xi; requirement and objectives, printed page 37
- 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)(xi)
GAVII Cybersecurity assessment approach
Connect the objective to the evidence
Identify all public-facing components in scope, including services hosted outside the office. If none exist, support the applicability decision with the actual architecture rather than assuming the requirement is automatically met.
Assessment focus: objectives [a], [b]. Use the methods together; a single example does not establish every objective.
Examine
Inspect public-service inventories, subnet and segmentation diagrams, firewall rules, and approved connectivity.
Interview
What prevents a public-facing component from reaching internal systems beyond its approved connections?
Demonstrate or test
Demonstrate representative allowed and denied paths between a public-facing segment and internal networks.
Evidence gaps to look for
- A public application shares unrestricted internal connectivity.
- An N/A claim overlooks a management or application endpoint exposed to the internet.
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: 5
If this requirement is NOT MET, deduct 5 points 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 has a deduction greater than 1 point and does not qualify for the limited encryption exception. 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 ↗SC.L2-3.13.5; requirement and objectives, printed page 221. 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 3.13.5. February 2020, updated January 2021.
- NIST SP 800-171A ↗Assessment procedure 3.13.5. 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.