NIST 800-171 3.4.7 (CM.L2-3.4.7): Nonessential Services

Restrict, disable, or prevent the use of nonessential programs, functions, ports, protocols, and services.

NIST SP 800-171 Rev. 2, requirement 3.4.7

CMMC Level 2 practice CM.L2-3.4.7Published 2026-11-11

What 3.4.7 means in practice

Go item by item: decide which programs, functions, ports, protocols and services are essential, and restrict, disable or block the rest. Typical examples are removing unused software, turning off SMBv1 or Telnet, and closing ports nobody uses.

SPRS points and the CMMC POA&M

CMMC Level 2 practice: CM.L2-3.4.7
SPRS points: 5 points. When it is not met, the DoD Assessment Methodology subtracts 5 from the score of 110.
CMMC POA&M: Not allowed. It is worth 5 points, and 32 CFR 170.21(a)(2)(ii) admits only requirements worth 1 point, with one exception: 3.13.11 when encryption is used but not FIPS validated.

Sources: NIST SP 800-171 DoD Assessment Methodology, version 1.2.1 (June 24, 2020), Annex A; 32 CFR 170.21, Plan of Action and Milestones requirements.

What an assessor checks for 3.4.7

NIST SP 800-171A gives 15 determination statements for 3.4.7, each found satisfied or other than satisfied. Determine if:

3.4.7[a] essential programs are defined.
3.4.7[b] the use of nonessential programs is defined.
3.4.7[c] the use of nonessential programs is restricted, disabled, or prevented as defined.
3.4.7[d] essential functions are defined.
3.4.7[e] the use of nonessential functions is defined.
3.4.7[f] the use of nonessential functions is restricted, disabled, or prevented as defined.
3.4.7[g] essential ports are defined.
3.4.7[h] the use of nonessential ports is defined.
3.4.7[i] the use of nonessential ports is restricted, disabled, or prevented as defined.
3.4.7[j] essential protocols are defined.
3.4.7[k] the use of nonessential protocols is defined.
3.4.7[l] the use of nonessential protocols is restricted, disabled, or prevented as defined.
3.4.7[m] essential services are defined.
3.4.7[n] the use of nonessential services is defined.
3.4.7[o] the use of nonessential services is restricted, disabled, or prevented as defined.

NIST SP 800-171A (June 2018), assessment objectives for 3.4.7

Evidence that shows 3.4.7 is met

Lists of the essential programs, functions, ports, protocols and services.
Firewall and host configuration showing the nonessential ones blocked or disabled.
Scan results showing only approved ports and services listening.

How PolicyCortex gathers the evidence

No PolicyCortex collector reads the evidence for 3.4.7. Your team provides the evidence listed above.

Related pages

Calculator: SPRS score calculator: mark 3.4.7 and the other 109 requirements and see the score.
Sample package: Sample package: an SSP, a POA&M and an evidence chain the product generated from demonstration data.
Family: All 9 Configuration Management requirements (3.4).
Previous: 3.4.6: Least Functionality
Next: 3.4.8: Application Execution
All requirements: All 110 NIST SP 800-171 requirements, by family.

Related records

Guides and articles describe the work. The evidence that work produces is described in three proof pages, the architecture page, and the two pages on authorization.

proof.state: Proof of State. What the environment was, as of a date someone else picks: point-in-time records, content hashed and chained.
proof.change: Proof of Change. Who or what altered the environment, under what authority, with before and after state hashes.
proof.agency: Proof of Agency. What a machine was permitted to do before it acted, what it did, and what would have stopped it.
architecture: Architecture. How the chain is built and where the evidence is stored in each delivery mode.
authorization: Continuous ATO. How an authorizing official's decision is recorded with its package, and how the authorized system is checked against it every hour.
baseline: NIST SP 800-53. The Low, Moderate and High baselines as evidence, with the SSP, SAR and POA&M generated from one record.