What is DNS and what are common DNS record types A, AAAA, MX, NS, and CNAME?

• A. DNS translates domain names to IPs; A maps IPv4, AAAA maps IPv6, MX for mail servers, NS for nameservers, CNAME for aliases.
• B. DNS translates IPs to domain names.
• C. DNS is used for DHCP.
• D. DNS is only for email.

Answer: (A)

DNS is the system that translates human-friendly domain names into the IP addresses computers use to locate resources on the Internet. When you look up a domain, DNS helps find the address so your browser can connect to the right server. Common record types include: A records map a domain to an IPv4 address; AAAA records map a domain to an IPv6 address; MX records specify which mail servers handle email for the domain and include priority to choose the preferred server; NS records indicate which servers are authoritative for the domain; CNAME records create an alias from one domain name to another domain name. Reverse lookups, which map IPs back to domain names, are a related function but not the general purpose of DNS. DHCP is a separate service, and DNS is not limited to email.