Firewall Rule Validator Calculator

Audit allow and deny rules before deployment securely. Spot shadowed entries, overlaps, and risky services. Export reports, compare variants, and enforce consistent standards daily.

Input Options
Accepts any, IP, or CIDR.
Supports lists and ranges.
Use narrow destinations when possible.
action protocol srcCIDR srcPort dstCIDR dstPort direction
Add “; comment” at the end if needed.
Lines starting with # are ignored. Max 200 lines.
Reset

Example Data

Examples show typical findings for common rules.

Rule Expected Risk Common Finding Suggested Fix
ALLOW TCP SRC any:any DST 10.0.0.10/32:22 DIR INBOUND High Open source with sensitive port. Restrict source CIDR and enable logging.
ALLOW TCP SRC 10.0.0.0/8:any DST 10.0.1.20/32:443 DIR INBOUND Low Narrow destination and explicit port. Keep scope limited; review overlaps.
DENY ANY SRC any:any DST any:any DIR ANY Low Broad deny at end of policy. Ensure allow rules are ordered above.

Formula Used

Risk scoring is a weighted sum of common exposure factors.

This helps prioritize review, not replace approvals.

How to Use This Calculator

  1. Choose Single Rule or Bulk Rules input.
  2. Enter action, protocol, direction, IP ranges, and ports.
  3. Use any only when business needs demand it.
  4. Click Validate Rules to view issues and risk ratings.
  5. Fix conflicts, tighten scope, and enable logging where needed.
  6. Download CSV or PDF to share with reviewers.

Related Calculators

Firewall Rule BuilderNAT Rule GeneratorFirewall Policy OptimizerPort Mapping CalculatorNAT Capacity EstimatorFirewall Throughput EstimatorRule Conflict DetectorPort Exposure CalculatorFirewall Change ImpactFirewall Compliance Checker

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.