DNS resolution is the process of translating human-readable domain names (like example.com) into machine-readable IP addresses (like 192.0.2.1). Here's a step-by-step breakdown:

1. User Enters Domain Name

The user types a domain name into their web browser or another application.

2. Local DNS Cache Check

The operating system (OS) first checks its local DNS cache to see if it has a recent record for that domain name. If found, it uses that IP address and the process ends here.

3. Resolver Query

If the domain is not in the local cache, the OS sends a query to a DNS resolver (often provided by your ISP or a public DNS service like Google DNS). This resolver is also known as a recursive DNS server.

4. Root Server Query

The resolver doesn't know the IP address directly, so it queries one of the 13 root DNS servers. These servers don't store specific domain information but know where to find the Top-Level Domain (TLD) servers.

5. TLD Server Query

The root server responds to the resolver with the IP address of the appropriate TLD name server (e.g., for example.com, it would point to the .com TLD server).

6. Authoritative Name Server Query

The resolver then queries the TLD name server, which responds with the IP address of the authoritative name server for the specific domain (e.g., the name server for example.com). This server holds the actual DNS records for the domain.

7. IP Address Retrieval

The resolver queries the authoritative name server, which finally provides the IP address associated with the domain name (e.g., example.com resolves to 192.0.2.1).

8. Caching and Response

The resolver caches this IP address for future requests and then sends it back to the user's OS. The OS also caches the IP address.

9. Connection Established

The user's browser or application now has the IP address and can establish a connection with the web server hosting example.com.