Connect to a local PostgreSQL server using peer auth with pgAdmin

# Context I have a [PostgreSQL](https://www.postgresql.org/) server running on a remote machine, but I'm connected locally through VPN. Its pg_hba.conf file is accepting peer auth for local connections; local all postgres peer I don't like to change this. If I follow what is written here: https://documentation.help/pgAdmin3/connect.html ; > The host is the IP address of the machine to contact, or the fully qualified domain name. On Unix based systems, the address field may be **left blank** to use the default PostgreSQL Unix Domain Socket on the local machine, or be set to an alternate path containing a PostgreSQL socket. If a path is entered, it must begin with a “/”. The port number may also be specified. I got this error on [pgAdmin3](https://www.pgadmin.org/) : I even tried not to leave the Host field blank but to write the name of the socket file in there: /var/run/postgresql -> the behaviour is the same. And if I insert postgresql:// instead, I get; An error has occurred: 07:55:28: Error: Error connecting to the server: could not translate host name "postgresql://" to address: Name or service not known And pgAdmin4 doesn't let me have the Host field blank: Until there, I was logged in as the normal Ubuntu user. So I decided to try while being postgres Ubuntu user, just like when I want to run a pg_* command using peer auth (e.g. $ sudo -u postgres pg_* -U postgres bla bla): pgAdmin3: $ sudo -u postgres pgAdmin3 Client is not authorized to connect to Server07:44:11: Erorr: Unable to initialize GTK+, is DISPLAY set properly? pgAdmin4: $ sudo -u postgres pgAdmin4 QStandardPaths: XDG_RUNTINE_DIR not set, defaulting to '/tmp/runtime-postgres' Client is not authorized to connect to Serverqt.qpa.screen: QXcbConnection: Could not connect to display :1.0 Could not connect to any X display. Next I decided to check this out on my local machine in order to by-pass these display related errors pgAdmin3: $ sudo -u postgres pgadmin3 No protocol specified 07:49:51: Error: Unable to initialize GTK+, is DISPLAY set properly? I do not have pgAdmin4 on my local machine, but I guess I will encounter some same kind of error. # Question How can I log to the local PostgreSQL server which is based on a peer authentication using pgAdmin3 or pgAdmin4? # Update: These three new lines were added to the log file in /var/log/postgres/postgresql-12-main.log after the unsuccessful connection using pgAdmin3: 2020-04-16 16:34:55.548 CEST postgres@postgres LOG: provided user name (postgres) and authenticated user name (ubuntumainusername) do not match 2020-04-16 16:34:55.548 CEST postgres@postgres FATAL: Peer authentication failed for user "postgres" 2020-04-16 16:34:55.548 CEST postgres@postgres DETAIL: Connection matched pg_hba.conf line 85: "local all postgres peer"