Domain Name System Resolution and Troubleshooting Questions

Deep understanding of the Domain Name System resolution process and the related operational concerns. Topics include the roles of recursive resolvers and authoritative name servers, zone delegation and glue records, common record types such as address records, canonical name records, mail exchange records, name server records, text records, and service records, and how time to live values affect caching and propagation. Candidates should be able to explain frequent failure modes such as misconfigured records, propagation delays, delegation mistakes, name server outages, and secure configuration problems, and demonstrate troubleshooting techniques using query tools and packet capture to trace queries and determine whether issues stem from authoritative sources, caches, transport, or configuration.