Testing a connection that should fail (for lack of pg_hba entry):
$ psql -h sss2 tgl
psql: FATAL: missing or erroneous pg_hba.conf file
HINT: See postmaster log for details.
$
Say what? This is with a completely default pg_hba.conf file...
looking in the postmaster log as suggested:
LOG: could not interpret IP address "::1" in config file: Unknown server error
LOG: invalid entry in pg_hba.conf file at line 55, token "::1"
FATAL: missing or erroneous pg_hba.conf file
HINT: See postmaster log for details.
In short, it will not do to put IPv6 addresses into pg_hba.conf
by default on machines where IPv6 support is not present.
While we could gin up some mechanism to adjust the installed copy of
pg_hba.conf.sample depending on whether we detected IPv6 support,
I am inclined to simply remove or comment out the IPv6-specific entry
in the sample file. I doubt that many people actually need it, and
the ones who do can just adjust the sample file.
Comments?
regards, tom lane