CompTIA A+ Core 1 (220-1201)NetworkingHard
A technician configures a device with only an automatically assigned IPv6 address that begins with fe80::. The device can communicate with other hosts on the same local network segment but not with hosts on other networks or the internet. Which of the following BEST explains this behavior?
- AThe device received a link-local address, which is not routable beyond the local subnet.
- BThe device received an APIPA address due to a failed DHCP request.
- CThe device's default gateway is configured with an invalid subnet mask.
- DThe device is using a deprecated IPv6 address that requires renewal.
Show answer & explanationAnswer & explanation
Correct answer: A. The device received a link-local address, which is not routable beyond the local subnet.
Addresses beginning with fe80:: are IPv6 link-local addresses, automatically assigned to every interface and valid only for communication within the local network segment; they are never routed beyond it. APIPA (169.254.x.x) is an IPv4-only concept, and there is no indication of a deprecated address or invalid subnet mask in this scenario.
Why the other options are wrong
- B. APIPA applies to IPv4 addresses (169.254.x.x), not IPv6.
- C. Subnet masks are not used the same way in IPv6, and this doesn't match the described symptom.
- D. Deprecated addresses are a valid IPv6 lifecycle state but not indicated by the fe80 prefix.
IPv6 Link-Local Address
An IPv6 link-local address, beginning with fe80::, is automatically assigned to every interface and is only valid for communication within the local network segment.
- Prefix range: fe80::/10
- Not routable beyond local subnet
- Every IPv6-enabled interface has one automatically
Memory trick: fe80 stays home — never leaves the local link.