Oracle Database Discussions

Hi,

I am taking a course in Database Concepts. I have installed Oracle on my PC, and have used my email address as my user name and password.

I want to start Oracle, and see if I can run a few SQL queries on the default database (if one is installed).

I have started SQL Plus, entered my user name and password (that being my email address), pressed enter, and the following message appears:

ORA-12170: TNS: Connect timeout occurred

I then followed the steps outlined by Burleson Consulting at:
http://www.dba-oracle.com/t_ora_12170_tns_connect_timeout.htm

That is, I:

Modified the SQLNET.INBOUND_CONNECT_TIMEOUT setting from 3 to 10

AND

Pasted 190.1.1.20 diogenes into the DNS hosts file.

All that happens now is that the ORA-12170: TNS: Connect timeout occurred message takes longer to appear.

Can anyone help me?

Thanks in advance.

Sean