On Wed, 28 Dec 2016, John R Pierce wrote:
> with psql, no -h  and -h localhost are two different connection types. if
> you don't specify a -h, it uses a 'unix domain socket',
   Thanks, John. I believe that I understand the differences. Here,
/var/lib/pgsql/9.6/data/pg_hba.conf contains:
# IPv4 local connections:
host    all             rshepard        192.168.55.0/24         trust
hostnossl all           rshepard        192.168.55.0/24         trust
   I've left the ipv6 line alone.
Regards,
Rich