What is Glue record?

A glue record is an IP address record, published by the registry, for nameservers that sit inside the domain they serve.

A glue record tells the internet the IP address of a nameserver when that nameserver's name is part of the same domain it's responsible for. Without it, nobody could find the nameserver in the first place.

Here's the problem it solves. Say example.com uses the nameservers ns1.example.com and ns2.example.com. To find the IP address of example.com, a resolver has to ask ns1.example.com. But to find ns1.example.com, it would have to ask the nameserver for example.com, which is ns1.example.com. That's a loop. A glue record breaks it by storing the nameserver's IP address at the registry, one level up.

How glue records work

When a resolver looks up a domain, it asks the registry servers for the TLD, such as .com, which nameservers handle the domain. Normally the registry replies with names only, and the resolver looks those up separately. If the nameservers sit inside the domain itself, the registry also sends their IP addresses. Those extra addresses are the glue.

A glue record contains just two things:

• The nameserver hostname, such as ns1.example.com.
• Its IP address, either IPv4, IPv6 or both.

When you need a glue record

You need glue records when you set up "child" or "private" nameservers, meaning nameservers named after your own domain. This is common for:

• Hosting resellers who want branded nameservers for their clients, often on reseller hosting.
• Companies running their own DNS servers.
• Anyone using a VPS or dedicated server with DNS software installed.

If you use your host's nameservers or a service like Cloudflare, you don't need glue records. Those nameservers live on other domains, and their own glue is already in place.

How to create a glue record

Glue records are created at your registrar, not in your hosting DNS zone. The option is often called "child nameservers", "host records" or "register nameservers". You enter the hostname and IP address, the registrar submits them to the registry, and only then can you use those names as nameservers for your domain.

Common glue record mistakes

• Adding an A record for ns1 in your zone file but never registering the glue at the registrar.
• Changing your server's IP address without updating the glue.
• Having the A record in your zone and the glue record point to different IPs.
• Setting up only one nameserver. Most registries expect at least two.

Glue record questions