IDENT Authentication Failed For Postgres. Pg_hba.conf

I just reloaded the OS on our production server and I'm having issues configuring postgres.

the user postgres exists in the system (i.e. 'su postgres' switches me to that user)
i attempted to connect to my database 'service_2_3' via CLI:

Code:
$ su postgres
$ psql service_2_3
and i recieved the following error:

Code:
psql: FATAL: IDENT authentication failed for user "postgres@service_2_3"
the database is installed on the machine on which i was attempting to connect to it with.

therefore, i edited my pg_hba.conf so that it looks like this:

Code:

# TYPE DATABASE USER CIDR-ADDRESS METHOD

# "local" is for Unix domain socket connections only
local all all ident sameuser
# IPv4 local connections:
host all all 127.0.0.1/32 ident sameuser
# IPv6 local connections:
host all all ::1/128 ident sameuser
host all all 0.0.0.0 0.0.0.0 password

and reloaded with (as user postgres):

Code:
bash-3.00$ pg_ctl reload -D /var/lib/pgsql/data -l /var/lib/pgsql/data/temp.log

but i still get the same error. am i editing the wrong file, perhaps?

how would i know which is the correct pg_hba.conf file?

locate pg_hba.conf seems to give me a few results.