16.2.1 Diagnosing Server Problems

To start diagnosing server problems, you should answer the following questions:

  • Is any other system such as a workstation or server able to connect to the server using Oracle Net?

  • Has the server, database, or listener configuration remained the same for some time?

If you answered yes to either of the preceding questions, then go to "Diagnosing Client Problems".

If you are unsure, or answered no to any of the preceding questions, then use the tasks in this section to diagnose the problem. Diagnosing Oracle Net Services on the server involves the following tasks:

Task 1   Verify the Database is Running

To check that the database is up, log in to the database and connect with a valid username and password. For example: 

SQLPLUS system
Enter password: password

A message appears, confirming that you are connected with the database. If you receive the following errors, then ask the database administrator to assist you:

  • ORA-1017: invalid U/P

  • ORA-1034: Oracle not available

Task 2   Perform a Loopback Test

A loopback test uses Oracle Net to go from the database server back to itself, bypassing the Interprocess Communication (IPC) protocol. Many network protocols provide a means of testing network connections. The PING utility can be used with a TCP/IP network. Performing a successful loopback verifies that Oracle Net is functioning on the database server.

The following procedure describes how to perform a loopback test from the server to the database:

  1. Ensure that the listener.ora, tnsnames.ora, and sqlnet.ora files exist in the correct locations, as described in "Using Localized Management".

  2. Start Oracle Net Manager.

    See Also:

    "Using Oracle Net Manager to Configure Oracle Net Services"

  3. In the navigator, expand the Directory or Local option.

  4. Expand Service Naming to view the available network service and database names.

  5. Select the network service name or database service.

  6. Choose Command, and then select Test Net Service.

    Testing assumes the listener and database are running. If they are not, then see "Starting Oracle Net Listener and the Oracle Database Server" to start components.

    During testing, a Connection Test dialog box appears, providing status and test results. A successful test results in the following message:

    The connection test was successful.

    If the test was successful, then proceed to step 7.

    If the test was not successful, then do the following:

    1. Ensure the database and listener are running, and then click Test.

    2. Click Change Login to change the username and password for the connection, and then click Test.

    • If the loopback test passes, then go to "Diagnosing Client Problems".

    • If the loopback test continues to fail, then contact Oracle Support Services.

  7. Click Close to close the Connect Test dialog box.

Parent topic: Diagnosing Oracle Net Services