Bài học theo mô-đun (3/3)
Interrogare e confrontare
Query and compare
Diagnostic tools such as dig let you ask a specific server for a specific name and type. Compare the configured recursive resolver with an authoritative server; inspect the answer, status, flags, TTL, and server address. An option that traces the delegation path can help show referrals, but output should be interpreted one step at a time.
Keep examples in a safe lab or use reserved names such as .test. When working with a real domain, make read-only queries and stay within your authorization. A tool’s output is evidence about that query at that time, not proof that every user sees the same answer.
Record the exact command, time, network vantage point, queried resolver, and result so another person can reproduce the observation. Change one variable at a time when comparing behavior.
Check your understanding
Choose the best answer. This quiz runs locally and sends no DNS queries to real domains.
What makes two DNS observations useful to compare?