Identifying a private IPv4 address | LinuC Level 1 102 Exam original practice question

1.07.1Basic

Choose an RFC 1918 private IPv4 address for internal LAN use.

Which address is private?

Hint 1: Focus on the requirement

Identify what must change and what must remain unchanged. Then choose the command whose scope matches that requirement.

Hint 2: Check each command's role

Separate commands that display information, change state, remove data, or affect a child process.

11.20.30.40: Incorrect. 11.20.30.40 is outside the RFC 1918 ranges.
169.254.20.30: Incorrect. 169.254.0.0/16 is link-local, not RFC 1918 private space.
192.0.2.40: Incorrect. 192.0.2.0/24 is TEST-NET-1 documentation space.
172.20.30.40: Correct. 172.20.30.40 lies within 172.16.0.0/12.

Detailed explanation

Incorrect11.20.30.40

Incorrect. 11.20.30.40 is outside the RFC 1918 ranges.

Incorrect169.254.20.30

Incorrect. 169.254.0.0/16 is link-local, not RFC 1918 private space.

Incorrect192.0.2.40

Incorrect. 192.0.2.0/24 is TEST-NET-1 documentation space.

Correct172.20.30.40

Correct. 172.20.30.40 lies within 172.16.0.0/12.

An example you can run in a temporary verification environment.

python3 -c "import ipaddress; a=ipaddress.ip_address('172.20.30.40'); print(a in ipaddress.ip_network('172.16.0.0/12'))"

True

Foundation review

Check whether the command acts on the current shell, a new process, an existing process, or a file.

Use the supplied command and compare the output with the expected result.

Question IDKL-102-944

EnvironmentPython 3 ipaddress / ローカル計算のみ

Last technical review2026-08-13