Domain Name System
DNS is the internet's naming system. Records like A, AAAA, CNAME, MX, and TXT answer questions about names.
Another example
Before moving a store, an engineer lowers TTL. They change the target, check resolvers, then restore TTL.
Main parts
- 01Originating request
- 02Resolution or processing hop
- 03Response, timing, and failure
Use it when
Use DNS records to connect names to services or prove ownership without fixed client addresses.
Do not use it when
Do not expect instant updates. Never delete unknown records or expose private names in public zones.
Name used in code
A / AAAA / CNAME / MX / TXT / TTL Before you ship
Check contracts and invariants, authorization, and input limits. Test retries, one-time effects, timeouts, and partial failures. Verify data integrity, compatibility, monitoring, recovery, and rollback.
Outcome: Design or review DNS for this system while keeping data correct, secure, and easy to operate. User context: Before moving a store, an engineer lowers TTL. They change the target, check resolvers, then restore TTL. Technical concept or control: DNS. Why it fits: Use DNS records to connect names to services or prove ownership without fixed client addresses. Do not use it when: Do not expect instant updates. Never delete unknown records or expose private names in public zones. Engineering requirements: Define inputs, outputs, contracts, and rules that must always hold. Set authorization and input checks. Define failures, timeouts, retries, one-time effects, data moves, and compatibility limits. Operations: Add useful signals and logs that hide sensitive data. Set capacity limits and write an operator guide. Test recovery and rollback. Acceptance criteria: Contract and failure-path tests pass. Data and authorization rules still hold during retries and partial failures. Check performance limits, monitoring, recovery, and rollback. Evidence and limits (evidence boundary): The standard covers only the listed scope. It does not choose the visual style, product decision, or Vibulary example. Unknowns to confirm: Where the code runs, data stores, traffic shape, consistency needs, and the security boundary. Also confirm the compatibility period, service goals, and rollback limits.
Check this request
Review the current use of DNS. Definition: DNS is the internet's naming system. Records like A, AAAA, CNAME, MX, and TXT answer questions about names. Release checks: Check contracts and invariants, authorization, and input limits. Test retries, one-time effects, timeouts, and partial failures. Verify data integrity, compatibility, monitoring, recovery, and rollback. Before changing code, report the evidence you found, gaps, severity, and the smallest safe fix.