What is a DNS Lookup?

A DNS (Domain Name System) lookup translates a human-readable domain name like example.com into the IP addresses and other records that computers use to route traffic. DNS is often called the "phone book of the internet."

DNS Record Types

TypeNameDescription
AAddressMaps a domain to an IPv4 address
AAAAIPv6 AddressMaps a domain to an IPv6 address
CNAMECanonical NameCreates an alias pointing to another domain
MXMail ExchangeSpecifies mail servers for the domain, with priority values
NSName ServerIndicates which DNS servers are authoritative for the domain
TXTTextHolds arbitrary text, commonly used for SPF, DKIM, and domain verification

How DNS resolution works

When you type a URL in your browser, your computer queries a DNS resolver (usually provided by your ISP or a public service like Google DNS at 8.8.8.8). The resolver walks the DNS hierarchy - from root servers, to TLD servers (like .com), to the domain's authoritative name servers - and returns the IP address your browser needs to connect.