DNS Zone Transfer Risk Calculator

Measure AXFR risk using practical security signal checks. Compare controls, permissions, and monitoring in minutes. Export reports and prioritize remediation for resilient DNS operations.

Enter DNS configuration signals

Use letters, digits, dots, dashes, underscores.
Higher counts can increase drift risk.
External tests are most meaningful.
Authentication reduces spoofed transfer requests.
Recursion can widen abuse surface.

Formula used

Risk score is the weighted sum of signals, clamped to 0–100.

Score = Σ(weightᵢ × conditionᵢ)
Score = min(100, max(0, Score))
  • Open AXFR adds 35 points.
  • No transfer policy adds 20 points; weak adds 10.
  • No ACL adds 10; no TSIG adds 10.
  • Internet exposure +5; recursion +5; no monitoring +5.
  • Unknown/outdated patch +5; no rate limiting +3; no DNSSEC +2.
  • More nameservers add up to +3 for drift risk.

How to use this calculator

  1. Enter the zone and authoritative server count.
  2. Select what you know about transfer controls and monitoring.
  3. Run external AXFR tests to confirm exposure when possible.
  4. Click Calculate Risk and review reasons and actions.
  5. Download CSV/PDF to share with your security team.

Tip: Treat “Unknown” selections as operational risk until verified.

Example data table

Illustrative inputs and computed score
Zone NS Policy Open AXFR ACL TSIG Exposure Recursion Monitoring Patch RRL DNSSEC Score Level
example.com 4 weak unknown no no internet yes no unknown no no 57 High

Example row shows how “unknown” and missing controls elevate risk.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.