DNSSEC validation problems usually happen when DS records at the registrar do not match DNSKEY records at the DNS provider, the zone is not signed, old DS records remain after nameserver changes, or DNSSEC was enabled before the provider was ready. Check current nameservers, DS records, DNSKEY records, zone signing, and validation results before making changes.
Who This Guide Is For This guide is for: · Users seeing SERVFAIL after DNSSEC changes · Domain owners who changed nameservers with DNSSEC enabled · Businesses with partial resolution failures · Agencies and hosting providers troubleshooting DNSSEC · Resellers supporting client DNSSEC
Before You Start Before you start, prepare: · Domain name · Current and previous nameservers · Registrar DNSSEC access · DNS provider access · Current DS records · DNSKEY values · Recent transfer or nameserver changes · Error screenshot · DNS backup
Step-by-Step Instructions Step 1: Confirm DNSSEC Is the Problem Look for SERVFAIL, validation failure, or failures only on validating resolvers. · Wrong IP or missing MX may be normal DNS misconfiguration Step 2: Check Current Nameservers DNSSEC must match the active DNS provider. · Old nameservers and new nameservers matter Step 3: Check DS Records at Registrar Record key tag, algorithm, digest type, digest, and whether multiple DS records exist. · Old DS records are common after migrations Step 4: Check DNSKEY at DNS Provider Confirm zone signing, DNSKEY, KSK/ZSK, and generated DS values. · Provider must sign the active zone Step 5: Compare DS and DNSKEY Mismatch causes validation failure. · Use fresh values from active DNS provider Step 6: Check Zone Signing Look for DNSKEY, RRSIG, NSEC/NSEC3, and provider signing status. · Unsigned zone plus DS records is risky Step 7: Remove Incorrect DS if Needed If wrong DS causes failure and correct setup is not ready, remove invalid DS to restore resolution. · Re-enable later with correct data Step 8: Re-Enable Correctly Stabilize nameservers, enable provider signing, add fresh DS, then verify. · Do not add DS before signing Step 9: Review Recent Transfer Check whether DS records or DNS provider changed during transfer. · New registrar may need DS review Step 10: Test Website and Email After validation is fixed, check A, CNAME, MX, TXT, SSL, and CDN. · DNSSEC affects all validated lookups Step 11: Document the Fix Save cause, DS changes, current provider, and test results. · Prevents future repeat issues
Troubleshooting Domain Shows SERVFAIL Possible reasons: · DS mismatch · DNSKEY missing · Zone unsigned · Old DS remains What to do: · Check DS/DNSKEY · Remove incorrect DS · Verify signing Failed After Nameserver Change Possible reasons: · Old DS points to previous provider · New provider not signed What to do: · Remove old DS or add new provider DS Failed After Domain Transfer Possible reasons: · DS not carried or changed · Old registrar DNS stopped What to do: · Review registrar-side DS and active DNS provider Email Failing After DNSSEC Possible reasons: · MX lookup fails validation · TXT records inaccessible What to do: · Fix DNSSEC first, then check email records
Common Mistakes Mistake 1: Changing nameservers without removing old DS Review this item before making changes or opening a support ticket. Mistake 2: Adding DS before signing active Review this item before making changes or opening a support ticket. Mistake 3: Copying DS values incorrectly Review this item before making changes or opening a support ticket. Mistake 4: Assuming DNSSEC is SSL Review this item before making changes or opening a support ticket. Mistake 5: Troubleshooting only A records Review this item before making changes or opening a support ticket. Mistake 6: Ignoring current nameservers Review this item before making changes or opening a support ticket. Mistake 7: Leaving multiple old DS records Review this item before making changes or opening a support ticket. Mistake 8: Making random changes during SERVFAIL Review this item before making changes or opening a support ticket. Mistake 9: Not testing validating resolvers Review this item before making changes or opening a support ticket. Mistake 10: Not documenting setup Review this item before making changes or opening a support ticket.
FAQ 1. What is DNSSEC validation failure? A resolver cannot verify signed DNS data for the domain. 2. What does SERVFAIL mean? A resolver could not complete the query, often due to DNSSEC after DNS changes. 3. What causes failure? DS mismatch, missing DNSKEY, unsigned zone, old DS records, or key rollover issues. 4. Should I remove DS records? If incorrect DS causes failure, removing it may restore resolution until DNSSEC is correctly re-enabled. 5. Why after nameserver change? Old DS may point to the previous DNS provider keys. 6. Can DNSSEC affect email? Yes, MX and TXT lookups can fail validation. 7. Can NiceNIC fix external DNSSEC? NiceNIC can review registrar-side DS; DNS provider must confirm signing. 8. Should I enable again later? Yes, after nameservers and signing are correct.