postgresql - What's the difference between "local" and "localhost" connection types in pg_hba.conf?

Question

This is the relevant part of my pg_hba.conf:

# TYPE  DATABASE        USER            ADDRESS                 METHOD

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

The pidentd service is running.

When I try to log onto ee1 (I assume, the default user is postgres) :

psql ee1 

It says "peer authentication failed for user postgres"

1. Where have I configured peer authentication for "postgres" ? It's ident.

2. When I change the following line in pg_hba.conf:

   local   all             all                                 ident
   

   to

   local   all             all                                 md5
   

   it asks me for a password, and I am able to log in. Why is it that making changes to the local connection type, have effect on postgres user?

Answer 1

ident authentication means that your OS user matches DB user. It is support only for TCP/IP connections as relevant entry in docs states. If used with Unix socket, Peer authentication method will be used instead.

Also, note, that default user is not postgres, but the one you're currently logged in with.