What evidence do auditors commonly ask for on SC-21 Secure Name/Address Resolution Service (Recursive or Caching Resolver)?

SSP SC-21 statement confirming recursive resolvers request and validate DNSSEC responses; Resolver configuration with DNSSEC validation enabled and a test query result; Boundary protection architecture with firewall and proxy rule documentation; Cryptographic standards specifying approved algorithms and key lengths; Key management procedures including rotation and escrow; TLS configuration scan results across in scope endpoints.

What is the most common gap auditors find on SC-21?

Firewall rule base contains stale allow any entries

FedRAMP High (NIST SP 800-53 Rev 5 baseline) · SC - System and Communications Protection

`SC-21` Secure Name/Address Resolution Service (Recursive or Caching Resolver)

Request and perform data origin authentication and data integrity verification on name/address resolution responses; DNSSEC validation.

Source: FedRAMP High (NIST SP 800-53 Rev 5 baseline), SC-21. 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 FedRAMP High (NIST SP 800-53 Rev 5 baseline) in the compliance library.

A FedRAMP baseline is a subset of NIST SP 800-53 Rev 5, enhancements included.

artefacts

held by a system

at each review

moderate

to go live

Cloud console / configuration management

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

Resolver configuration with DNSSEC validation enabled and a test query result · Cloud console / configuration management
TLS configuration scan results across in scope endpoints · Vulnerability scanner / patch tooling

periodic reviewEvidence produced at each review

none for this control

governing documentDocuments that govern the control

SSP SC-21 statement confirming recursive resolvers request and validate DNSSEC responses · Document repository
Boundary protection architecture with firewall and proxy rule documentation · Policy repository / GRC workspace
Cryptographic standards specifying approved algorithms and key lengths · Policy repository / GRC workspace
Key management procedures including rotation and escrow · Policy repository / GRC workspace

First move

Start with the 2 of 6 artefacts that already live in a system (Cloud console / configuration management); keep the periodic reviews but log each one as a dated record with a named reviewer.

Common gaps auditors find

Firewall rule base contains stale allow any entries
Internal traffic between services unencrypted within trusted zones
Legacy TLS versions remain enabled on external services

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-20 Secure Name/Address Resolution Service (Authoritative) · SC-22 Architecture and Provisioning for Name/Address Resolution Service