Mail to example.com is bouncing and you want to see which mail exchangers the domain publishes. Type the complete command, using the host utility and the option that selects a record type, that queries only the MX records of example.com.
LPIC-1 Exam 102-500, objective 109. Networking fundamentals medium
Machine-checked — no person has signed for it. This question was read against the source cited below by an automated pass, which found no contradiction. That is a weaker claim than it sounds: the same kind of process wrote the question, so it can confirm its own mistake.
Treat it as a good draft rather than as settled fact, and read the source below before you rely on it. It is not used in mock exams here — only questions a person has signed for are.
How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
Answer
Type the answer.
Accepted answers
host -t MX example.comhost -t mx example.comhost -tMX example.comhost -tmx example.com
Case sensitive — Linux is, and grading LS as ls would teach a falsehood.
Why
host -t TYPE NAME restricts the query to one record type; without -t, host asks for A, AAAA and MX records and prints whatever comes back. Record type names are matched case-insensitively, so MX and mx behave alike. The equivalent with the other common client is `dig example.com MX`, where the type is a bare trailing argument rather than an option.
Where this comes from
- Cited
- manual page host(1)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 109 and space the ones you get wrong.
More questions on this objective
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