Database connection failed in arc catalog

Database connection failed in arc catalog

I am trying to connect from Arc Cataloge (version 10.1) to postgresql 9.2.
But every time I try to make "Database Connection" I am getting this
error:
Failed to connect to the specified server.
Underlying DBMS error[could not connect to server: Connection timed out
Is the server running on host"x.y.z.w" and accepting TCP/IP connections
on port 5432?
Postgresql is installed on Centos server (PORT 5432) and I can access it
using pgadmin. In the instance field i put "x.y.z.w" since the IP addreess
of the server was this.
I also put "postgresql-client-libraries" in /bin directory of ArcGIS for
Desktop.
I appreciate any help.