DNS servers translate domain names into IP addresses so that computers can process them. Domain name systems label websites with descriptors that are accessible for human users, rather than an IP address in numerical format. A computer network processes IP addresses; DNS servers bridge the gap by performing a search process for the IP address that corresponds to the domain name that a user has entered (webopedia.com, for example). Different DNS servers perform different parts of the query and return process. A DNS resolver, which is responsible for initiating the search for an IP address, begins the DNS process by making queries to servers.
Types of DNS servers
A recursive DNS server searches other servers after receiving a query from the DNS resolver. The recursive server keeps copies of cached IP address records for a period of time, so if the IP address has been recently accessed, the recursive server may be able to pass it directly back to the user’s application.
A root name server receives a query from the recursive server and searches the top-level domain (TLD) servers for the corresponding IP address.
Top-level domain servers categorize the top level domains (such as .com or .org). When a root name server makes a request to the appropriate TLD server, that server will then search only the relevant domain.
Authoritative name servers are the last resort of a DNS server query process. They store all IP address records. An authoritative name server will return the IP address record to the recursive server, and the recursive server will send it to the computer/application that made the initial request.
