Discuss how Internet Directory Service Domain Name System look up service to provide a mapping between the name on host and its numerical address

 The Domain Name System (DNS) is a critical component of the Internet infrastructure that provides a hierarchical naming system for computers, services, and other resources connected to the Internet or a private network. DNS enables the mapping of domain names to IP addresses, allowing users to access web pages, send emails, and use other network services using human-readable names rather than numerical IP addresses.

When a user enters a domain name into their web browser, the browser sends a request to a DNS resolver to obtain the IP address associated with that domain name. The DNS resolver then performs a series of queries to locate the authoritative name server for the domain name in question. The authoritative name server is responsible for storing the mapping of the domain name to its IP address.

The DNS resolver queries the authoritative name server by sending a recursive query, which starts at the root of the DNS hierarchy and moves down the hierarchy until it reaches the authoritative name server for the domain in question. The recursive query process involves multiple DNS servers, and each server caches the results of previous queries to reduce the load on the network.

Once the DNS resolver obtains the IP address for the domain name, it returns the IP address to the user's web browser, which then uses the IP address to connect to the appropriate server and retrieve the requested web page.

The DNS system provides several benefits, including:

1. Human-readable domain names: DNS enables users to access web pages and other network services using human-readable domain names rather than numerical IP addresses.

2. Scalability: The DNS system is highly scalable and can handle millions of queries per second.

3. Load balancing: DNS can be used to distribute network traffic across multiple servers, improving performance and reliability.

4. Redundancy: DNS supports multiple name servers for a domain, providing redundancy and improving reliability.

In conclusion, the Domain Name System (DNS) is a critical component of the Internet infrastructure that provides a hierarchical naming system for computers, services, and other resources connected to the Internet. DNS enables the mapping of domain names to IP addresses, allowing users to access web pages, send emails, and use other network services using human-readable names rather than numerical IP addresses.