The Domain Name System (DNS) is a decentralized system that serves as the "phone book" of the internet, translating human-readable domain names (such as "example.com") into IP addresses (such as "192.0.2.1"), which are numerical identifiers used by computers to locate resources on the internet.

DNS plays a crucial role in the functioning of domain names and the internet as a whole by providing a distributed and hierarchical naming system. When you enter a domain name into your web browser's address bar, your device queries DNS servers to resolve the domain name to its corresponding IP address. This process allows your device to locate the appropriate web server hosting the requested website's content.

Here's how the DNS resolution process works:

1. DNS Query: Your device sends a DNS query to a DNS resolver, typically provided by your internet service provider (ISP) or configured in your network settings.

2. Recursive Query: If the DNS resolver doesn't have the requested DNS record cached locally, it performs a recursive query. It starts by querying the root DNS servers, then the top-level domain (TLD) servers, and finally the authoritative DNS servers responsible for the specific domain.

3. DNS Response: The authoritative DNS server for the requested domain responds with the corresponding IP address, which is then returned to your device through the DNS resolver.

4. Connection Establishment: Your device establishes a connection to the web server hosting the requested website using the IP address obtained from DNS resolution. The web server then serves the requested web page back to your device.

By translating domain names into IP addresses, DNS enables seamless communication and connectivity across the internet. It's a fundamental component of the internet's infrastructure, facilitating the navigation and accessibility of websites and online services for users worldwide.