DNS Delegation Broken
Broken DNS delegation (also called "lame delegation") occurs when the nameservers specified at the registrar do not actually host the DNS zone for the domain. This causes intermittent or complete resolution failures because resolvers query nameservers that cannot answer authoritatively for the domain.
Symptoms
- Domain works intermittently depending on which NS is queried
- Some resolvers return SERVFAIL while others work
- WHOIS shows nameservers different from actual DNS hosting
- DNS checks report "lame delegation" warnings
Common Causes
- Nameservers changed at registrar without migrating the zone
- DNS hosting provider account expired or zone deleted
- Mistyped nameserver hostnames at the registrar
- Secondary nameserver removed from DNS provider but still listed at registrar
- Domain transferred to new registrar without updating NS records
Step-by-Step Troubleshooting
- 1
Check NS records at registrar
Verify the nameservers listed in WHOIS match your DNS hosting provider.
Use WHOIS Lookup → - 2
Query each nameserver directly
Test each listed nameserver to see if it responds authoritatively for the domain.
Use NS Record Lookup → - 3
Verify zone exists on nameservers
Confirm the DNS zone is active and contains records at your DNS provider.
Use DNS Records Dump → - 4
Update NS records at registrar
Correct the nameserver delegation at your registrar to point to the servers actually hosting your zone.
- 5
Wait for propagation
After fixing delegation, allow 24–48 hours for resolvers to pick up the updated NS records.
Use DNS Lookup →
Recommended Diagnostic Tools
Monitor DNS Delegation
Get alerts if nameserver delegation becomes broken or inconsistent.