Every time you open a browser and type a domain name such as `google.com` or `microsoft.com`, your computer translates that text name into a numerical **IP address** that routing networks can understand. This phonebook service of the internet is called the Domain Name System (DNS). Knowing how it works helps resolve browser connectivity loops.
Common DNS resolver concepts
DNS Server
A remote network computer that responds to name requests by returning the matching IP code.
Local DNS Cache
A temporary list of recently resolved site names saved directly on your computer to save speed.
DNS Flush (ipconfig)
Flushing clears out corrupted name listings from the computer RAM, forcing a fresh lookup request.
DNS Server Unreachable
Appears when local router settings cannot resolve contact links to ISP name servers.
How Name Resolution Works
When you click a link or type a URL in your web browser, the computer follows a clear step-by-step path to locate the page data:
1. **Check Local Cache**: The operating system searches the local client-side memory. If the domain is found, it loads immediately. 2. **Ask the Router**: If missing, the request is pushed over the gateway to your home router. 3. **Query ISP DNS**: If the router doesn't have it, it queries your Internet Service Provider's (ISP) DNS servers or public recursive resolvers (like Cloudflare 1.1.1.1 or Google 8.8.8.8). 4. **Connect to Web IP**: Once the correct IP address is returned, the browser establishes a handshake connection.
The DNS Server Hierarchy
If a lookup request is not cached, the DNS query travels through a chain of hierarchical servers to locate the authoritative record:
- DNS Recursor: The gatekeeper server (usually run by your ISP) that manages the lookup search queries.
- Root Nameserver: The first directory stop. It redirects the recursor to the specific Top-Level Domain (TLD) server based on the extension (e.g. .com or .org).
- TLD Nameserver: Manages records for all domains with that extension and points the search to the specific registry host.
- Authoritative Nameserver: The final stop. This server holds the exact IP mapping record and returns the IP address code (like 172.217.7.14) to your computer.
Why flush the DNS cache?
If a website changes its server IP address but your computer is still using the old IP saved in its local cache, you will get a "Page Cannot Be Found" or "Limited Connectivity" error. Flushing the DNS cache (using the command `ipconfig /flushdns` in Command Prompt) clears the slate, requesting the updated IP address from the router.