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IPv4 addressing

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A host comes up with an address in 169.254.0.0/16 and no default gateway. What does that tell you?

Answer

The link is up at layer 2 and DHCP is not answering

Link-local self-assignment is what an interface falls back to when DHCP does not answer, which makes it a useful diagnostic rather than a failure in itself: the interface is up and able to check the segment for address conflicts, and the DHCP exchange is the part that is broken. No server assigns it — the host picks the address itself, which rules out the first option. A static misconfiguration is possible in principle but would be an odd range to choose by hand, and the absence of a gateway is the giveaway that this is the automatic fallback. Nothing about IPv6 produces a 169.254 address.

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