DNS resolution is the process that converts URLs into IP addresses, effectively mapping human-readable web addresses to the unique IP addresses of servers.

The Domain Name System (DNS) is a critical component of the internet’s infrastructure, functioning as a directory that associates devices with their corresponding IP addresses. When you enter a URL into your web browser, the DNS resolution process is initiated, which involves several steps to translate the URL into an IP address that your computer can comprehend and utilize to access data from the correct server.

The first step in this process involves your computer checking its local DNS cache, which stores information about recent DNS lookups. If the IP address corresponding to the URL is found in the cache, the process concludes here. However, if the information is not available, the request proceeds to the next stage.

Next, the DNS query is sent to a recursive DNS server, typically managed by your internet service provider (ISP). This server also maintains its own cache. If it does not possess the necessary information, it forwards the query to a root DNS server. While the root server does not have the specific IP address, it can direct the query to a Top-Level Domain (TLD) server, which contains information about domains under specific extensions such as .com or .org.

The TLD server then directs the query to an authoritative DNS server, which holds the actual DNS records for the specific domain. These records include the IP address associated with the domain name. The authoritative server responds by sending the IP address back to the recursive server, which caches this information for any future queries and subsequently relays it to your computer.

Finally, your computer stores the IP address in its local DNS cache and provides the address to your browser. The browser then establishes a connection with the server at that IP address to retrieve the web page you requested. Remarkably, this entire process occurs in a matter of milliseconds, making it seem instantaneous to the user.

In summary, DNS resolution is a multi-step process that involves several servers, each playing an essential role in translating a URL into an IP address that your computer can use to access data from the internet.