Checking IPv6 Path MTU numerically | LinuC Level 1 102 Exam original practice question

1.07.3Basic

Use a regular user account to inspect IPv6 path and Path MTU to 2001:db8::20.

Do not perform reverse DNS.

Which command is appropriate?

Hint 1: Focus on the observed layer

Separate interface counters, sockets, DNS lookups, path tracing, and routing changes before comparing the diagnostic commands.

Hint 2: Key terms

Review the short definitions of interface counters, sockets, DNS, path tracing, and routes involved.

tracepath: A diagnostic command that reports a path and its Path MTU.
-6: A tracepath setting that selects IPv6.
-4: A tracepath setting that selects IPv4.
-n: A setting that displays addresses numerically without name lookup.
Path MTU: The largest packet size that can cross a path without fragmentation.

Detailed explanation

Incorrecttracepath -4 -n 2001:db8::20

Incorrect. -4 forces IPv4.

Correcttracepath -6 -n 2001:db8::20

Correct. It traces the IPv6 path and shows numeric Path MTU data.

Incorrectss -6 -n 2001:db8::20

Incorrect. ss lists local sockets, not a path or Path MTU.

Incorrectroute -6 -n 2001:db8::20

Incorrect. route handles the local table and does not probe every hop.

An example you can run in a temporary verification environment.

tracepath -h 2>&1 | sed -n '1,10p'

-4、-6、-nなどを含むtracepathの使用方法

Foundation review

Kernel-maintained counts of packets, errors, and drops at an interface.

A local or remote endpoint associated with a transport protocol and process.

A diagnostic method that observes hops and path limits toward a destination.

Question IDKL-102-998

Environmentiputils tracepath help / 外部通信なし

Last technical review2026-08-13

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