The NS in NS records stands for name servers. NS records tell you which name server is authoritive for the domain/subdomain. A single domain can often have more than one NS record, which may mean that there is a primary and secondary/backup name server for that domain. There are two main reasons that administrators use NS records:
- They want to delegate part of their domain/subdomains to use different name servers.
- They want to separate traffic to their domain between their local name servers and other name servers.
When you create NS records, the value that you enter for each record is the fully-qualified domain name (FQDN) that you want to point the NS record to. When you do a name server lookup, you enter the domain in the search and see which name server(s) contain the NS record.