How DNS server works and the types of DNS server.
As you type some alphabetic addresses in the URL, what happens next? How did the web browser show you the result? It's all done by Domain Name System. It is like a phonebook for websites, you just have to remember their hostname, no need to remember IP addresses. This is what a DNS does - Resolve hostname to corresponding IP addresses. It is an Application layer protocol. It uses both UDP and TCP. It works on port number 53. There are 4 types of DNS - Recursive Resolver (DNS resolver), Root Nameserver, Top-level domain server, and Authoritative nameserver. 1. Recursive Resolver - It is the first domain name server. When your device wants to find the IP address associated with the hostname. A DNS query is sent by the DNS client (web browser). Then, the query goes to Recursive Resolver. Recursive resolver operated by ISP (Internet Service Provider), which stores the IP address in its cache. ISP further sends the query to the Root name server if do not find it...