What are Glue Records / Child Nameservers / Private Nameservers?

Glue records are the binding (or glue) of IP addresses to your nameservers, e.g.

ns1.domain.com = 8.8.8.8
ns2.domain.com = 8.8.4.4

Glue records are held at the parent (GTLD / ccTLD / sGTLD) nameservers.

Example Scenario: Domain Nameservers Without Glue Records

Here’s an example scenario of a domain that does not have Glue records configured for its nameservers:

  1. [Guest] Hi, domain.com, what are your nameservers?
  2. [Host] Hi, Guest, my nameservers are ns1.domain.com and ns2.domain.com
  3. [Guest] Fantastic, I’ll head over there now. Could you provide me with the IP addresses so I can reach them?
  4. [Host] Sorry, I don’t know the IP addresses of the nameservers.
  5. [Guest] Okay, I’ll try ns1.domain.com and ns2.doman.com again.

Immediately, you will notice that the guest is now stuck in a loop as the IP addresses of the nameservers were not provided upon lookup.

Example Scenario: Domain Nameservers With Glue Records

Here’s an example scenario of a domain that has Glue records configured for its nameservers:

  1. [Guest] Hi, domain.com, what are your nameservers?
  2. [Host] Hi, Guest, my nameservers are ns1.domain.com and ns2.domain.com
  3. [Guest] Fantastic, I’ll head over there now. Could you provide me with the IP addresses so I can reach them?
  4. [Host] Sure, the IP addresses are 8.8.8.8 and 8.8.4.4.
  5. [Guest] Great, I’ve reached your nameserver IP’s and can query domain.com for its records

Now, we can see that the guest can successfully reach the nameservers because the exact locations (IP addresses) have been provided. The guest can now poll the nameserver for its appropriate records.

 

Example DNS Lookup