Choosing an IPv4 loopback address | LinuC Level 1 102 Exam original practice question

1.07.1Basic

Communicate with the TCP/IP stack on the same host without sending packets to a physical network.

Which address is a representative loopback?

Hint 1: Focus on protocol roles

Separate reliable transport, datagram transport, IP control messages, and name resolution before comparing the choices.

Hint 2: Key terms

Review the short definitions of transport protocols, control messages, and name resolution involved.

IPv4 loopback: The 127.0.0.0/8 range used to address the local host.
Unspecified address: A special value meaning that no interface address has been selected.
Link-local: An automatically configured range limited to the local link.
Broadcast: A delivery mode that sends to multiple hosts on one network.

Detailed explanation

Incorrect0.0.0.0

Incorrect. 0.0.0.0 is an unspecified address in contexts such as binding.

Correct127.0.0.1

Correct. 127.0.0.1 is the standard loopback address.

Incorrect169.254.0.1

Incorrect. 169.254.0.1 is link-local.

Incorrect255.255.255.255

Incorrect. 255.255.255.255 is the limited broadcast address.

An example you can run in a temporary verification environment.

python3 -c "import ipaddress; print(ipaddress.ip_address('127.0.0.1').is_loopback)"

True

Foundation review

The part of an IP address that identifies the network rather than a host.

TCP and UDP provide different delivery, reliability, and connection semantics.

A numbered endpoint used to deliver traffic to a network service.

Question IDKL-102-946

EnvironmentPython 3 ipaddress / 外部通信なし

Last technical review2026-08-13

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