Configuring DNS

- How DNS Works

There are four DNS servers involved during the processing of a DNS query in the backend:

• DNS recursor: The recursor can be thought of as a librarian who is asked to go find a particular book somewhere in a library. The DNS recursor is a server designed to receive queries from client machines through applications such as web browsers. Typically, the recursor is then responsible for making additional requests in order to satisfy the client’s DNS query.
• Root nameserver: The root server is the first step in resolving the human readable host names into IP addresses. It can be thought of like an index in a library that points to different racks of books, typically it serves as a reference to other more specific locations. There are 13 such root name servers distribute all across the globe, and manages by different independent organisations.
• TLD nameserver: The top level domain server (TLD) can be thought of as a specific rack of books in a library. This nameserver is the next step in the search for a specific IP address, and it hosts the last portion of a hostname (In example.com, the TLD server is “com”). There are over 750 such TLDs currently present all over the globe.
• Authoritative nameserver : This final nameserver can be thought of as a dictionary on the specific rack of books, in which a specific name can be translated into its definition. The authoritative nameserver is the last stop in the nameserver query. If the authoritative name server has access to the requested record, it will return the IP address for the requested hostname back to the DNS Recursor (the librarian) that made the initial request.