SC-22·critical·Component: System and Communications ProtectionWhat this control requires
Ensure that the systems providing name/address resolution services for the organization are fault-tolerant and implement internal and external role separation. This involves deploying at least two authoritative DNS servers (primary and secondary) to eliminate single points of failure and enhance redundancy. These servers are typically placed in geographically separated subnetworks to ensure availability. Additionally, role separation is enforced, with DNS servers handling internal requests only from within the organization and external requests only from clients outside the organization. This control supports the DNS Server Architecture and Role Management System capability within the System and Communications Protection family.
In plain English
Ensure that the systems providing name/address resolution services for the organization are fault-tolerant and implement internal and external role separation. In practice, this means you can prove you access management-level controls on a defined cadence.
Why it matters
SP 800-53 is the catalogue every U.S. federal authorisation (FedRAMP, FISMA, CMMC) and most regulated industries point at. A missing control surfaces as a Plan of Action & Milestones (POA&M) item that an Authorizing Official must approve before the Authority To Operate is granted or renewed.
This control is rated critical in the source catalogue. Treat gaps here as production incidents in the risk register, not housekeeping.
What an auditor looks for
A 3PAO (FedRAMP) or Independent Assessor (NIST RMF) tests against NIST SP 800-53A assessment procedures. For each control they expect a documented implementation that addresses every assessment objective (Examine, Interview, Test) and an implementation summary in the System Security Plan.
Within System and Communications Protection, the assessor will trace your implementation back to the catalogue reference (Control SC-22) and look for objective evidence on the latest two assessment cycles.
How to implement
- Write a short policy stating intent, scope and named owner.
- Encode it as a platform guardrail — SCP, Azure Policy initiative, Organisation Policy, or repository policy.
- Wire a monitoring signal that catches drift (CSPM rule, SIEM rule, scheduled query, Workspace alert) and ticket it.
- Review on a documented cadence and capture the review in the risk register or compliance tracker.
Operational checklist
- Access. Document the trigger, the owner and the cadence.
- Internal. Document the trigger, the owner and the cadence.
- Separation. Document the trigger, the owner and the cadence.
- Least. Document the trigger, the owner and the cadence.
- Review. Document the trigger, the owner and the cadence.
- Scope: management, organization, system, service, only, failure, protection, identity.
Evidence to collect
- Identity Scan. IAM / IdP exports — Entra ID, Okta, IAM Identity Center, Workspace directory — showing accounts, roles, MFA state and last sign-in.
Identity analytics (Okta, SailPoint, Access Analyzer) demonstrates least-privilege. Focus: Architecture And Provisioning For Name/Address Resolution Service.
How it maps to other frameworks
Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.
- CIS Controls v8 5.6 — Centralize Account Management
- NIST SP 800-171 Rev. 3 3.13.4 — Information in Shared System Resources
Related controls in NIST SP 800-53 Rev. 5
- Control SC-8(5) — Protected Distribution System
- Control SC-20(2) — Data Origin And Integrity
- Control SC-7(28) — Connections To Public Networks
- Control SC-7(3) — Access Points
- Control SC-7(14) — Protect Against Unauthorized Physical Connections
- Control SC-21 — Secure Name/Address Resolution Service (Recursive Or Caching Resolver)
References
- NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
- Catalogue identifier:
Control SC-22
Topics: identity accessidentity managementaccess reviewprivileged access