Common Errors During Testing

• An invalid listener name was typed in the LSNRCTL START command.

Check your typing. Check the LISTENER.ORA file to ensure that the listener name you are using is valid.

• Files were put in the wrong place.

Both the listener and the Interchange will indicate that they cannot start because configuration files could not be found. Check your operating system-specific documentation to see that the LISTENER.ORA file has been placed correctly on the listener machine, and the INTCHG.ORA, TNSNAV.ORA, and TNSNET.ORA files are placed correctly on the Interchange machine. (Refer to "Testing the Network Configuration" in this chapter, and to the Oracle Network Products Troubleshooting Guide for more information.)

If you are using TNSNAMES.ORA files, make sure they were created with Network Manager, and not created by hand. If you are using Oracle Names Servers, make sure they have been started. Also make sure that NAMES.ORA is placed correctly, and that SQLNET.ORA file contains the preferred Names Server parameter. If a native naming service such as NIS is in use, make sure that the appropriate Native Naming adapter has been installed on clients and servers, and that service names have been properly loaded into it. Refer to your operating system-specific documentation for information.

• Address already in use.

Another process may already be using the address listed in LISTENER.ORA. On some protocols such as TCP/IP, DECnet, and OSI, each network service on a node must use a unique port or socket. On other network protocols such as SPX/IPX or NetBIOS, each network service name must be unique for the entire network. Another network service may be using the same configuration. Contact your network administrator to evaluate whether the network address is available.

• When trying to connect to a database, you may get the message ORA-12203: "TNS:Unable to connect to destination" .

Use the LSNRCTL utility to start the listener on the server machine. See Appendix C for further information.

• When trying to make a connection from a client, you may get the message ORA-12154:"TNS:Could not resolve service name".

The service name you requested is not listed in the TNSNAMES.ORA file, or the TNSNAMES.ORA file has been placed incorrectly. See Appendix C for further information.

• When trying to connect to a database, you may get the message ORA-1034: "Oracle Not Available".

The database is not running on the server machine. A listener alone does not provide a database connection; the database instance must also be started.

• Connect requests that come in too quickly for a listener to handle, and which exceed the listener's backlog (determined by QUEUESIZE parameter in LISTENER.ORA, TNSNET.ORA, and NAMES.ORA), are returned with an ECONNREFUSED error. A client encountering this error returns the message "ORA-12541: No Listener" and the client log or trace files will show the ECONNREFUSED message.

To correct this problem, follow these steps:

• Stop the listener.

• Reconfigure QUEUESIZE in LISTENER.ORA, TNSNET.ORA, or NAMES.ORA to be a larger value (based on anticipated simultaneous connect requests).

• Restart the listener.

• Try to connect again.

Refer to "Increasing the Queue Size for the Listeners" in Appendix A for information on increasing the number of connection requests the listener can handle.

• When attempting to stop the listener, you may get the message TNS-01169: "The listener has not recognized the password." Enter the SET PASSWORD command from within LSNRCTL, and then enter the STOP command to stop the listener.