NS Lookup

What is NS lookup?

A nameserver (NS) lookup is a type of domain name system (DNS) record that’s used to retrieve the server name in which the domain details are stored. It helps to connect the domain name with its internet protocol (IP) in a human-friendly approach. In layman's terms, a DNS record can also be known as the phone book of the internet, with NS being an integral part of it.

Why do we need NS records?

An NS record helps you identify the server in which the IP address of your domain exists. For instance, when a user enters zoho.com in the search bar, the search engine will send a request to the domain name server, which, in return, gives the IP of the domain. With this IP, the browser again makes a request for the website's content and will display it in the browser.

How to perform an NS lookup?

To get the NS record for any domain, type the domain name in the NSlookup tool. The result will give you the hostname and the name server followed by its time-to-live (TTL) record. A typical NS would look like any other domain name, but they help us to reach the website.

Here’s an example of what an NS record looks like:

• ns-32.yourdomain.com
• ns.yourdomain.org

What records do NS lookups hold?

DNS records are stored in a repository that has multiple levels of servers, namely local servers, recursive DNS servers, and authoritative DNS servers. When a user hits a domain name, it will first try to locate its IP in the local cache. If the information isn’t available at the local end, it will direct the request to the recursive DNS.

The recursive DNS acts like a host computer and will cache the IP address through a request from an authoritative DNS server. This server doesn't store any DNS records; it will check its cache memory to see if the address record, otherwise known as the A record, of that particular website is present. If not, it will ping another recursive server until it reaches the authoritative DNS server.

If another query is requested for the A record of the same website, it can easily retrieve it from its local end. Generally, these cached records have TTL value—once they expire, the recursive DNS will query for an updated copy of them.

Authoritative DNS servers, on the other hand, stores the DNS records (e.g., MX, TXT, SOA, A, AAAA, etc.). When the server has the A record or the AAAA record for the website that’s been pinged, that server will be the authoritative DNS server for that particular domain. The NS record points out the authoritative server for a domain.