Understanding SQL*Net
Use the Oracle Network Manager
Once you have done the planning, made your decisions, and gathered the information you need, you are ready to configure the network. To do this, use Oracle Network Manager. This tool makes creating the configuration files relatively easy. Equally important, it helps you make them error free.
You will find complete instructions about the use of Network Manager in the Oracle Network Manager Administrator's Guide.
After you have created and distributed the configuration files, you can start and use the network. Information about using the network is, "Using SQL*Net".