I think the weirdness comes from the use of multiple addresses at once, specifically fe80::whatever addresses always being present and getting used even on normal setups when everything's working fine and a global address is configured, as opposed to 169.254.whatever addresses, which most networks never intend to use and so usually only show up when something is wrong.

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nine_k an hour ago | parent [-]

Isn't 127/8 always present in IPv4, without I'll consequences?

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josephcsible an hour ago | parent [-]

I meant it's one address per interface, and loopback has always been its own interface.

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trumpdong 41 minutes ago | parent [-]

One address per host is more common in serious networks that don't have endless IP addresses (10/8 block) allocated to them.

	▲	dcrazy 26 minutes ago \| parent [-]
		There is no problem with allocating one 127.0.0.0/8 to every interface on your host, because 127.0.0.0/8 is only ever accessible to the host itself. So even if you have multi-homed a single routable IPv4 address to 2 NICs on your server (for redundancy), you can still assign 127.0.0.1 to the first and 127.0.0.2 for the second, which you can then use to bind a port to a specific interface in the pair. (I don’t know if anyone actually does this.)