WHAT IS A DNS? INTRODUCTION TO THE DOMAIN NAME SYSTEM
The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or any resource connected to the Internet or a private network. It translates easily memorable domain names, like “example.com,” into numerical IP addresses, which are needed to locate and identify computer services and devices worldwide. In simpler terms, it’s like the phone book of the internet, mapping human-friendly domain names to machine-friendly IP addresses.
Here’s a brief overview of how DNS works:
1.Domain Names: Every website or service on the internet has a unique domain name, such as google.com, amazon.com, etc. These domain names are organized hierarchically, with the top-level domain (TLD) at the end (.com, .org, .net, etc.), followed by second-level domains (e.g., google, amazon), and sometimes subdomains (e.g., mail.google.com).
2.DNS Servers: The DNS system consists of a network of servers distributed globally. These servers store databases containing domain name-to-IP address mappings. DNS servers can be categorized into different types, including authoritative DNS servers, recursive DNS servers, and caching DNS servers.
3.DNS Resolution: When you type a domain name into your web browser, your computer needs to know the corresponding IP address to connect to that website’s server. It starts by querying a DNS resolver, which could be provided by your internet service provider (ISP) or a public DNS resolver like Google’s 8.8.8.8.
4.Recursive Query: If the resolver doesn’t have the IP address in its cache, it will recursively query other DNS servers until it finds one that can provide the mapping. It typically starts by querying one of the root DNS servers, which direct it to the appropriate top-level domain server, then to the second-level domain server, and so on, until it reaches the authoritative DNS server for the specific domain.
5.Response: Once the authoritative DNS server is found, it returns the IP address associated with the requested domain name to the resolver. The resolver caches this information for future use and sends the IP address back to the user’s device, allowing the web browser to establish a connection with the desired website or service.
Overall, the DNS plays a crucial role in ensuring that internet users can easily access websites and services by translating human-readable domain names into machine-readable IP addresses. Without DNS, navigating the internet would be much more challenging, as users would have to remember and input long strings of numbers for every website they want to visit.