Summary

DNS is the domain_name_system that translates a domain_name to an ip_address. It uses dns_records like a_record, aaaa_record, cname, and mx to answer queries. A recursive_resolver asks root_servers, then tld servers, then the authoritative_server. Results are stored with a ttl for caching. Most queries use udp_port_53; large transfers may use tcp. Zone data lives in zone_files. Remember: names to numbers, hierarchical lookup, and cached answers speed repeated requests.