Postgres User Can Login without a password

Hi there,

I have a situation that is a bit strange.
I discovered today that I can login in programs like EMS SQL Manager and in
the internal software (via ODBC) without using the password for the user.

Example:
Configuration on the ODBC:
datasource: postgres
database: Postgres
server: "IP"
user: 123456
password: 123456

The software connect to the ODBC getting the configs of the data source.
And when I clear the password in the ODBC the software continues to work,
without a passwd error.
I certified with the programers, and the software doesn't pass the password.

So, reading a little bit, I discovered that possibly my pg_hba.conf is
wrong.
I tried to change the "auth-method", but or I couldn't connect to the base
(if I pass the user and the passwd) or I connected without the passwd.

If someone get a ideia of what to do in this case, would be greatful.

Tnhks all,

Rafael