Why Does DNSSEC Validation Fail?
Understanding DNSSEC validation failures and how to fix them
Table of Contents
Why Does DNSSEC Validation Fail?
DNSSEC validation fails due to: signature verification failures (RRSIG signatures don't match DNSKEY public keys), chain of trust breaks (DS records don't match DNSKEY records), expired signatures (RRSIG signatures have expired), key mismatches (wrong DNSKEY used for verification), missing records (required DNSSEC records are missing), and configuration errors (incorrect DNSSEC setup).
Common causes include: expired RRSIG signatures, DS record mismatches, DNSKEY rotation issues, missing DNSSEC records, and incorrect DNSSEC configuration.
Learn more about DNSSEC, RRSIG records, and DS records.
Signature Verification Failures
What Causes Signature Failures?
Signature verification fails when RRSIG signatures cannot be verified using DNSKEY public keys, indicating DNS records may have been tampered with or signatures are invalid.
Common Causes
- RRSIG signatures don't match DNSKEY public keys
- Wrong DNSKEY used for signature verification
- Signature algorithm mismatches
- Corrupted signatures or keys
Impact
Signature verification failures cause DNSSEC validation to fail, resulting in DNS records being rejected by DNS resolvers.
Fixing Signature Failures
Fix signature failures by: ensuring RRSIG signatures match DNSKEY records, verifying correct DNSKEY is used, and re-signing DNS records if needed.
Chain of Trust Breaks
What Causes Chain Breaks?
Chain of trust breaks when DS records in parent zones don't match DNSKEY records in child zones, breaking the cryptographic chain from root DNS servers to authoritative name servers.
Common Causes
- DS records don't match DNSKEY records
- DNSKEY rotation without updating DS records
- Missing DS records in parent zones
- Incorrect DS record configuration
Impact
Chain of trust breaks cause DNSSEC validation to fail, preventing DNS resolvers from verifying DNS records across zone boundaries.
Fixing Chain Breaks
Fix chain breaks by: updating DS records to match DNSKEY records, ensuring DS records are published in parent zones, and verifying chain of trust is properly configured.
Expired Signatures
What Causes Expired Signatures?
RRSIG signatures expire after a set time period (signature expiration date), requiring DNS records to be re-signed with new signatures.
Common Causes
- RRSIG signatures past expiration date
- DNS records not re-signed before expiration
- Incorrect signature expiration configuration
- Missing signature renewal process
Impact
Expired signatures cause DNSSEC validation to fail, resulting in DNS records being rejected even if they're authentic.
Fixing Expired Signatures
Fix expired signatures by: re-signing DNS records with new RRSIG signatures, setting up automatic signature renewal, and monitoring signature expiration dates.
How to Fix Validation Failures
1. Identify the Issue
Use DNSSEC validation tools to identify specific validation failures (signature failures, chain breaks, expired signatures).
2. Fix Signature Issues
Fix signature verification failures by ensuring RRSIG signatures match DNSKEY records and re-signing DNS records if needed.
3. Fix Chain of Trust
Fix chain of trust breaks by updating DS records to match DNSKEY records and ensuring DS records are published in parent zones.
4. Update Expired Signatures
Re-sign DNS records with new RRSIG signatures before expiration dates to prevent validation failures.
5. Verify Configuration
Verify all DNSSEC records (DNSKEY, DS, RRSIG) are present and correctly configured.
6. Test Validation
Test DNSSEC validation after fixes to ensure validation works correctly and DNS records are accepted.
