On RPI3,
Prior to LE 9 Milhouse #1025, ".local" hostnames used to successfully resolve.
However with #1025, 25-Oct-2017: RPi / RPi2 -- Release post (Bump jsoncpp, avahi and nss-mdns)
".local" hostnames no longer resolve, instead getting eg
> ping DESK09.local
ping: bad address 'DESK09.local'
/lib no longer has an entry for mdns_minimal.so.2
and
/etc/nsswitch.conf still has
hosts: files mdns_minimal [NOTFOUND=return] dns
No machine on the network has an explicit ".local" address
".local" hostnames resolved prior to #1025, and problem still exists with #1201