NS Record

A Nameserver Record indicates which authoritative nameserver contains the actual DNS records

  • Basically, NS records tell the Internet where to go to find out a domain's IP address
  • Each authoritative nameserver in our DNS Zone should have an NS record.
    • ex. if we have 2 nameservers, we should have 2 NS records.

A domain often has multiple NS records which can indicate primary and backup nameservers for that domain.

  • if one nameserver goes down or is unavailable, DNS queries can go to another one
  • Typically there is one primary nameserver and several secondary nameservers, which store exact copies of the DNS records in the primary server
    • Updating the primary nameserver will trigger an update of the secondary nameservers as well.

Without properly configured NS records, users will be unable to load a website or application.

When multiple nameservers are used (as in most cases), NS records should list more than one server

NS records must point to an A record

  • ex. the resolver may have the NS records, but no A record, and it will still be able to query those nameservers directly, rather than having to go through the TLD server

Updating NS records

  • Domain administrators should update their NS records when they need to change their domain's nameservers
  • update NS records if you want a subdomain to use different nameservers than the domain (ex. example.com and blog.example.com have 2 different nameservers)