DNS security combines controls with different purposes. Validating DNS data, protecting a transport path, applying resolution policy and keeping resolvers available are separate requirements. Start an enterprise review by naming the problem each control is intended to address, then decide how the controls fit the actual resolution path.
This is an architecture review framework. It does not assume that every function discussed is included in a particular ZDNS product or deployment.
Separate validation from transport privacy
DNSSEC adds origin authentication and integrity for DNS data; it does not provide query confidentiality or general denial-of-service protection. RFC 4033 defines that boundary.
DNS over TLS protects a DNS transport connection using TLS. It addresses a different layer from signed DNS data. RFC 7858 describes the protocol and its focus on the stub-to-recursive path.
For an enterprise design, draw where validation takes place and where each encrypted connection begins and ends. Do not label the entire architecture “secure DNS” without identifying those boundaries.
Make policy enforcement a separate design decision
Decide which resolution requests should be allowed, blocked or handled as exceptions. Identify who owns that decision and how a user can report a mistaken block. A security policy that cannot be explained to the help desk is difficult to operate consistently.
Keep internal name resolution and business exceptions in the review. Ask how the proposed controls interact with remote users, branch networks and existing resolvers. These are questions to test against the intended architecture, not capabilities to assume from a feature name.
Use a control map in the design workshop
- Data validation. Question for the design team: Where are DNS answers validated?; Suggested evidence: Documented validation behavior and test
- Transport protection. Question for the design team: Which connection is protected?; Suggested evidence: Endpoint and authentication configuration
- Resolution policy. Question for the design team: Where is the decision enforced?; Suggested evidence: Policy test and exception record
- Availability. Question for the design team: What happens when a dependency fails?; Suggested evidence: Failure exercise with application checks
- Investigation. Question for the design team: Who can explain a DNS event?; Suggested evidence: Defined logs, access and investigation workflow
Use the checklist to expose gaps between teams. Each row should have an accountable owner and an agreed verification method before production enforcement.
Test a complete business journey
Propose a pilot covering ordinary resolution, an approved policy test and a dependency failure. Check the application as well as the resolver response. A successful DNS response does not by itself prove that a user completed the intended business task.
Record the client path, resolver selection, policy version and observed outcome. When the pilot behaves unexpectedly, investigate that path before adding broad exceptions. Keep rollback instructions available to the people operating the pilot.
Connect the design to product evaluation
ZDNS describes recursive resolution, upstream health monitoring and failover on its DNS product page. Use that information to begin a requirements discussion, then request confirmation of security functions, deployment conditions and evidence for the configuration being considered.
Questions about DNS security
Does DNSSEC encrypt queries?
No. Its purpose is DNS data validation, as described in RFC 4033.
Does encrypted DNS replace policy design?
No. Define the approved resolver path and the policy applied there separately.
Is a block count a complete success measure?
Include business continuity, exception handling and coverage checks in the evaluation.
Should all controls be activated together?
Use the organization's change process and a pilot that makes the effects of each change assessable.
What should I send ZDNS?
Share the resolution-path diagram and control requirements. Ask for the supported configuration and an agreed validation plan for your environment.