EvidenceSheet
CMMC 2.0 · System and Communications Protection

SC.L2-3.13.6 Network Communication by Exception

Deny network communications traffic by default and permit only traffic explicitly allowed by exception.

Source: CMMC 2.0, SC.L2-3.13.6. The statement above is our statement of the clause, read from the published text and cited so you can check it against the official text, not the instrument verbatim. Open CMMC 2.0 in the compliance library.

3
artefacts
1
held by a system
1
at each review
moderate
to go live
Identity provider / directory
where the evidence lives
teal = a system already holds it · olive = produced at each review. To go live: easy when half or more of the artefacts are already held by a system, moderate from a quarter to a half, hard below a quarter.

These are the artefacts auditors commonly ask for on this requirement, our guidance rather than text from the standard. Your assessor decides what is sufficient in your context, and asks for samples across the period when a report covers one.

system holds itEvidence a system already holds

  • Firewall and access control lists showing a default deny posture · Identity provider / directory

periodic reviewEvidence produced at each review

  • Review records for permitted exceptions · Document repository

governing documentDocuments that govern the control

  • Documented and approved exceptions with justification · Document repository

First move

Start with the 1 of 3 artefacts that already live in a system (Identity provider / directory); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

Do this for your whole sheet

Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.

Build my evidence sheet

SC.L2-3.13.5 Public-Access System Separation · SC.L2-3.13.7 Split Tunneling