How DNS works for domains and IP addresses
Domain Name System (DNS) is a system that connects domain names (e.g., example.com) to IP addresses (e.g., 192.0.2.1). When you type a domain name into your web browser, the DNS system is responsible for converting that domain name into an IP address that the computer can understand and use to access the internet.
Here’s a simple explanation of how it works:
- Query: When you type a domain name into your web browser, the computer sends a DNS query to a DNS resolver.
- Resolution: The DNS resolver then searches for the IP address associated with the domain name in a database called the DNS database.
- Caching: If the DNS resolver has already looked up the IP address for that domain name recently, it may have it stored in its cache. If it does, it returns the cached IP address to the computer.
- Root server: If the DNS resolver doesn’t have the IP address in its cache, it sends a query to a root server. The root server provides a list of top-level domain (TLD) servers.
- TLD server: The DNS resolver then sends a query to the TLD server responsible for the TLD of the domain name (e.g., .com, .org, .net).
- Authoritative server: The TLD server returns the IP address of an authoritative server that is responsible for the specific domain name.
- Response: The authoritative server returns the IP address for the domain name to the DNS resolver, which then sends it back to the computer.
- Connection: The computer then uses the IP address to establish a connection to the website or internet resource associated with the domain name.
So, in summary, the DNS system acts like a directory service for the internet, allowing you to access websites and other internet resources using human-readable domain names instead of numerical IP addresses.
Dave is a 20-year computer tech, systems administrator, and Geek.
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