The Nintendo Switch has been observed to hold on to IP addresses even after
their expiration. My guess is that this is an oversight: likely the device
enters power saving mode with a configured IP address and just sleeps through
the expiration time.
As the device seems to wake up once every hour, we enforce a minimum lease time
of 1 hour, but only for affected devices. The rest of the network gets short
lease times.
https://twitter.com/zekjur/status/1263949112036282374
Turns out a5d9e03dd3212f7f0c11dd856b308a16a58a3cdf was not entirely sufficient:
even though reused addresses would not be handed out anymore, they would still
be offered, which results in the client not being able to obtain an address.
Preferring unicast over multicast (which hogs a lot of airtime on WiFi networks)
is a best practice.
Some device/access point vendor combinations even seem to entirely eat (some?)
broadcast traffic (sometimes), e.g. my Apple iPhone SE/Ubiquiti UAP-AC-HD, so
that using unicast is required for reliable WiFi.
