Create listener.ora

Question: I have worked with Oracle for awhile on a local setup.  Now, I am tasked with creating a new database that will run on a network.  How do I create the sqlnet.ora, tnsnames.ora and listener.ora files?  Are they created automatically? If so, can I edit them as needed?

Answer:  Normally, the Oracle Net Configuration Assistant (NETCA) is launched during the software installation by the Oracle Universal Installer.  If NETCA runs successfully, the sqlnet.ora, tnsnames.ora and listener.ora files will be created automatically with default settings.  If NETCA does not succeed, it is possible to create the files manually.  Follow the links to more detailed information on creating and editing the sqlnet.ora and tnsnames.ora files.

The listener.ora file contains the server side network configuration parameters.  It is usually located in the ORACLE_HOME/network/admin directory.

During a standard installation on the database server, NETCA automatically configures a listener in the listener.ora file.  It is given the name LISTENER and it has a TCP/IP listening protocol address for the Oracle database.  For more advanced or custom installs, NETCA will prompt you and you can configure a listener name and protocol of your own choosing.

Regardless of whether you are configuring the listener during a basic or custom install, a listening IPC protocol address is automatically configured.  It is used for external procedure calls.

A basic listener.ora file might look like the following:

LISTENER=
  (description=
    (address_list)=
      (address=(protocol=tcp)(host=fu-bar)(port=1521))
      (address=(protocol=ipc)(key=extproc))))
sid_list_listener=
  (sid_list=
    (sid_desc=
      (sid_name=plsextproc)
      (oracle_home=/oracle11g)
      (program=extproc)))

Oracle Net Manager can be used to customize the listener.ora file.

For example, to configure one or more Listening Protocol Addresses, use the following steps by accessing the Net Services Administration page in Oracle Enterprise Manager:

1. From the Administer list, select Listeners
   Select the Oracle home that contains the location of the configuration files
2. Click Go to access the Listeners page
3. Select a listener
4. Click Edit to access the Edit Listener page
5. In the Addresses section, configure protocol support:
   1. Click Add to access the Add Address page
   2. From the Protocol list, choose the protocol upon which the listener is configured to listen
   3. Enter the parameter information for the selected protocol.
      The default port of 1521 should be used when configuring the listener to listen on TCP/IP. Failure to do so requires configuration of the local_listener parameter in the intialization parameter file and resolving the listener name through a naming method.
   4.  For computers with more than one IP address, if it is important for the listener to listen on all availalbe IP addresses, you will need to configure TCP/IP or TCP/IP with SSL and enter the host name of the computer in the host field.
6. Click OK to add the protocol address to the Addresses section.

This can be repeated as many times as necessary to add listener protocol addresses.

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