Two machines: the anchor raises the foundation, joins over its own
loopback and becomes the hub; the joiner makes its tunnel key, is issued
a token for it and enrols with the bus's port closed to its own address,
so the enrolment can arrive only over the tunnel (novox/hq ADR 0169). The
check that had been added to the two-node walk moves here, closing the
port the bundle publishes the bus on rather than the bus's own.
And the uplink's range may be named: behind a VPN client that routes
every private range, incus had none left to pick and no scenario could
be raised.
