problem to connect

Hye

I use linux mandrack 9.0 and postgres 7.2
I can't connect to postgresql (even in local) if I use a postgres user.
I don't know what to do.
I've started the daemon (root# etc/rc.d/init.d/postgresql start)
logged under postgres I made a user (createuser nico) and a database(createdb test)
But I can't access to this database if I am logged under an other user.
(su Eddy or anathor linux user)

When I try: psql test -h localhost -U nicolas I have the message :
IDENT authentification failed for user nicolas.
I can see the same message when I try to connect whith pgaccess.

If I try to start pgaccess with: "pgaccess test", the main PgAccess window
comes up, (empty) but there is an error message box in front of it. The message is:

"Error trying to connect to database "test" on host localhost.
is the postmaster running (with -i) at
'localhost' and accepting connections on TCP/IP port '5432'?"

Therefore I stopped postgresql etc/rc.d/init.d/postgresql stop
I started it logged under postgres with options ($ postmaster -h localhost -i )

I logged under another linux user
I tried : psql test -h localhost -U nicolas and received the message

No pga_hba.conf entry for host localhost, user nicolas, database test

I tryed to change the pg_dba.conf (trust) file but another message appears.

I would like to know what to do especially to use pgaccess

Please, help me !
regards

Nicolas RENIE