Question

Explain how the DNS is working.

Answer 1

1. When the user enters the URL (consists of a protocol, domain name, folder name, filename) in the browser, the system fist checks its DNS cache for the corresponding IP address.
2. If the IP address is found in the cache then the information is retrieved from the cache.
3. If not, then the system needs to perform a DNS query i.e., the system needs to query the resolver about the IP address from Internet Service Provider (ISP).
4. Each resolver has its own cache and if it is found in that then that information is retrieved.
5. If not, then the query is passed to the next domain server i.e., TLD (Top Level Domain) which reviews the request and directs the query to name servers associated with that specific domain.
6. Until the query is solved it is passed to next level domains. At last, the mapping and the record are returned to the resolver who checks whether the returned value is a record or an error.
7. Then the resolver returns the record back to the computer browser which is then viewed by the user.
   
   Workflow of basic DNS