We're using Oracle 9.2.0 on Linux RH9 and have tailored/modified the Oracle install for use with one of our products. As part of the changes we make to the install, there is no "listener.ora" file, nor is there a "tnsnames.ora" file. However, everything is working fine regarding the Listener. That is, I can stop and restart it and I can also perform listener functions like "tnsping". In addition, our own product which is installed on a separate machine, can communicate with the Oracle DB. Since there is no "listener.ora" nor "tnsnames.ora" files, how does Oracle provide connectivity to its clients?

Thank you,