How Does DNS Work? Record Types and Resolution Steps
What happens behind the scenes when you type a domain into your browser? We explain recursive resolution, record types and the TTL concept step by step.
What is DNS?
DNS (Domain Name System) is a distributed system that translates domain names into IP addresses. People prefer to type domain names, while machines talk in IP addresses. DNS connects these two worlds.
Resolution steps
- The browser asks the operating system's resolver.
- The resolver checks its cache first, then the root servers.
- The root server refers it to the relevant top-level domain (TLD) server.
- The TLD server points to the domain's authoritative server.
- The authoritative server returns the requested record; the result is cached for the TTL duration.
Commonly used record types
- A / AAAA: IPv4 and IPv6 addresses.
- CNAME: An alias that points one name to another.
- MX: Mail servers.
- TXT: Verification and policy text (SPF, DMARC, etc.).
- NS: The domain's authoritative name servers.
- CAA: Certificate authority restrictions.
TTL and caching
TTL (Time To Live) specifies how long a record is kept in cache. A low TTL makes changes appear faster; a high TTL reduces query load.
Summary
Understanding the DNS structure is the foundation for diagnosing propagation issues, email delivery problems and security configurations. With NetQuery you can query all of these records on a single screen.