Identify an IPv6 unicast address usable only on the local link and not routed beyond it.
Which address is link-local?
IPv6 link-local unicast uses fe80::/10. It supports same-link operations such as neighbor discovery and is normally not routed.
Detailed explanation
2001:db8::20Incorrect. 2001:db8::/32 is documentation global-unicast space.
Incorrect. 2001:db8::/32 is documentation global-unicast space.
fc00::20Incorrect. fc00::/7 is unique-local space.
Incorrect. fc00::/7 is unique-local space.
fe80::20Correct. fe80::20 belongs to fe80::/10.
Correct. fe80::20 belongs to fe80::/10.
ff02::20Incorrect. ff00::/8 is multicast.
Incorrect. ff00::/8 is multicast.
Try it yourself
An example you can run in a temporary verification environment.
python3 -c "import ipaddress; print(ipaddress.ip_address('fe80::20').is_link_local)"Expected result
TrueKey points
- fe80::/10
- Same-link use
- Not routed by routers
Notes
- Environment: Python 3 ipaddress / 外部通信なし
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.