Put simply, a glue record is an IP address that is "glued" to a domain or subdomain and saved in the zone of the particular registry.
You need a glue record if you want to use, for a particular domain, a name server that is a subdomain of the domain. This additional A/AAAA record allows the name server's IP address to be correctly resolved.
Creating the Glue Record
You can create a glue record for the domain by accessing the Manage Domains section in 1&1 IONOS:
- Select a domain and click the Nameserver tab.
- Then click the option Use custom name servers and enter the chosen subdomain as your primary name server in the Name Server 1 box.
- Once you have entered a subdomain of the domain as the domain's name server, additional boxes automatically appear.
- Enter the name server's IPv4 address and, if necessary, the IPv6 address.
- Enter the remaining name servers in the additional fields.
- Click Save.
The subdomains are created automatically and the name server settings are changed.