I followed this the advice I read here:
     https://superuser.com/questions/704785/ping-cant-resolve-hostname-but-nslookup-can:

     SOLUTION: the last suggestion on that page suggested checking on
     the validity of /etc/hosts.  I had originally replcaed /etc/hosts
     with the one from http://hosts-file.net/?s=Download.  there was
     something weird with it going --I tried overwriting it with the
     stock hosts file I had retained in case anything screws up; it
     timed out (the cp command just hung there!) So eventually I
     logged in with a sudo sh, then copied the stock hosts file to
     /etc/hosts.  THEN shit worked.

     So in short I think 16.04 was fine with that hostsfile from
     https://hosts-file.net/?s=Download but 16.10 is not.