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Dentro un messaggio DNS
Inside a DNS message
A DNS message has a header and up to four sections: question, answer, authority, and additional. The header includes an identifier, flags, and counts. The question says which name and type the client wants. The other sections carry data or directions that help continue resolution.
The QR flag distinguishes query from response. AA indicates an authoritative answer; TC signals truncation; RD requests recursion; RA says recursion is available; AD is used by validating resolvers to indicate authenticated data to a client in configured contexts. These flags must be read together with the server and transport: none alone tells the whole story.
When inspecting output, identify who sent the response and whether it is authoritative, recursive, truncated, or authenticated. Do not assume that every record in the additional section is the requested answer.
Check your understanding
Choose the best answer. This quiz runs locally and sends no DNS queries to real domains.
What does the TC flag indicate?