I know this question has been asked several times before, but all answers I could find tell you to add a line like the following to the pg_hba.conf file:
host all all 127.0.0.1/32 md5
So my pg_hba.conf file now looks like this:
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all peer
# IPv4 local connections:
host all all 127.0.0.1/32 ident
# IPv6 local connections:
host all all ::1/128 ident
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local replication postgres peer
#host replication postgres 127.0.0.1/32 ident
#host replication postgres ::1/128 ident
# I've added the following lines:
host all all 127.0.0.1/32 trust
host all all ::1/128 trust
host all all 127.0.0.1/32 md5
host all all ::1/128 md5
host all all 192.168.0.0/24 md5
I have set up several postgresql servers in the past on ubuntu and never had a problem. However, on fedora, I still get the following error message:
FATAL: Ident authentication failed for user "postgres"
The server is running on Fedora 27 Workstation and the postgresql version is 9.6.8-1.fc27.
You have two authentication rules for localhost in your pg_hba.conf, namely ..
host all all 127.0.0.1/32 ident
and
host all all 127.0.0.1/32 trust
I believe the system is trying to validate the two authentication options, making the trust option being overwritten by ident. Since you're most likely trying to use trust to authenticate from localhost (based on your file), just comment/delete the following line:
host all all 127.0.0.1/32 ident
And afterwards either restart your database or reload the conf file using the following query:
SELECT pg_reload_conf();