What is wrong with this identification configuration?

This is the idenfication setup in my /var/lib/pgsql/data/pg_hba.conf

local all trust
host all 127.0.0.1 255.255.255.255 trust

This is supposed to authenticate any user to be able to access my
postgresql system any time, no?

But this is what happened ( I tried to "log in" the template1 database
with root, postgres system account and my own user account)

[root(at)Monet wweng]# su postgres
bash-2.05a$ psql template1
psql: FATAL 1: No pg_hba.conf entry for host localhost, user postgres,
database template1

bash-2.05a$ exit
[root(at)Monet wweng]# psql template1

psql: FATAL 1: No pg_hba.conf entry for host localhost, user root,
database template1

[root(at)Monet wweng]# exit
[wweng(at)Monet wweng]$ psql template1
psql: FATAL 1: No pg_hba.conf entry for host localhost, user wweng,
database template1

Why is this happening? And how can I log in the template1 database?

I am using postgresql 7.2.3 on Redhat 7.3.

bash-2.05a$ rpm -qa | grep postgresql
postgresql-7.2.3-5.73
postgresql-libs-7.2.3-5.73
postgresql-server-7.2.3-5.73
postgresql-devel-7.2.3-5.73

Thanks a lot!

Wei