The Domain Name System (DNS) maps human-readable domain names to network addresses and other DNS records. It lets a browser resolve a URL such as https://www.example.com before initiating a web request. section 7.7
A typical lookup follows the hierarchy: a resolver asks a root server about .com, then asks the relevant domain server about example.com, and finally requests the address for www.example.com. Multiple servers and caches make this process scalable. section 7.7
Resolving a web address
When a browser visits https://www.example.com, the host operating system’s DNS resolver obtains the corresponding IP address, often from browser, operating-system, ISP, or corporate-network caches. section 7.7
DNS also creates a security boundary: attackers can target resolvers and caches with DNS poisoning to redirect users toward malicious sites. section 7.7
