DNS, or the Domain Name System, is a system that is used to translate human-friendly website addresses (like www.google.com) into the IP addresses (like 18.104.22.168) that computers use to locate and communicate with each other on the internet.
When you type a website address into your browser, your computer sends a request to a DNS server to resolve the domain name to an IP address. The DNS server looks up the IP address associated with the domain name in its database and sends it back to your computer. Your computer then uses that IP address to connect to the website’s server and retrieve the webpage.
DNS is essentially a hierarchical system of servers that work together to map domain names to IP addresses. At the top level, there are the root servers, which contain information about the top-level domains (like .com, .org, etc.). When a DNS server receives a request for a domain name, it first checks its cache to see if it has recently looked up that domain name. If not, it sends a request to a root server to find the appropriate top-level domain server.
The top-level domain server then sends a request to the appropriate second-level domain server (like google.com) which contains information about the specific domain name you requested. Finally, the second-level domain server sends back the IP address associated with the domain name.
DNS is an essential part of how the internet works, as it allows us to use easily memorable domain names instead of having to remember long strings of numbers as IP addresses. Additionally, it allows for the use of multiple IP addresses for a single domain name, which allows for website load balancing and failover.
It’s important to note that DNS is a distributed system, meaning that there are many DNS servers around the world that work together to resolve domain names. This allows for redundancy, so if one DNS server goes down, another one can take over, ensuring that domain name resolution can continue to take place.