Glossary
DNS RECORDS

Glue Record

An A or AAAA record in the parent zone giving the IP of an in-bailiwick nameserver. Solves the DNS chicken-and-egg where a nameserver is inside the zone it serves.

Glue Record solves the DNS bootstrapping problem when a domain’s nameservers live inside the domain itself. If example.com’s NS records point to ns1.example.com, a resolver can’t resolve ns1.example.com without first querying example.com’s nameservers — which requires resolving ns1.example.com first. Chicken and egg.

How Glue Fixes It

The parent zone (e.g., the .com zone) publishes A/AAAA records for the child’s nameservers, alongside the NS delegation. These “glue” A records break the loop.

Where You’ll Encounter It

Only when your nameservers are subdomains of the zone they serve — the “in-bailiwick” case:

example.com.        NS   ns1.example.com.
example.com.        NS   ns2.example.com.
ns1.example.com.    A    203.0.113.1
ns2.example.com.    A    203.0.113.2

The last two records are the glue — they must be submitted to the registrar so they get published in the parent zone.

Common Miss

Registering nameservers as ns1.mysite.com and ns2.mysite.com (in-bailiwick) without submitting glue A records to your registrar. The domain silently fails DNSSEC and returns SERVFAIL from validators. Fix: either submit the glue, or use out-of-bailiwick nameservers like ns1.hosting-provider.com.

Check the nameserver glossary entry, the NS record entry, and read what an SOA record is.

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