DNS & Domain Names

The Domain Name System (DNS)

DNS is the phonebook of the Internet. It translates human-readable domain names into machine-readable IP addresses.

DNS Record Types

• A Record: Maps a domain to an IPv4 address
• AAAA Record: Maps a domain to an IPv6 address
• CNAME: Creates an alias pointing to another domain
• MX: Directs email to mail servers
• TXT: Stores text information (SPF, DKIM verification)

TTL (Time to Live)

Each DNS record has a TTL value that tells resolvers how long to cache the record. Lower TTL means faster propagation but more DNS queries.