How to solve the problem that Oracle cannot listen to the program

When using Oracle database, we often encounter some problems. Among them, being unable to monitor the program is one of the more common errors. This problem will cause the database to fail to start, and may even affect the normal operation of the entire system.

So, when we encounter the error that the program cannot be monitored, how should we solve it?

1. Confirm whether the listener is started

When there is a problem that the program cannot be monitored, the first step to confirm is whether the listener is started. You can view the status of the listener by running the command lsnrctl status. If the listener is not started, you need to start the listener first with the command: lsnrctl start.

2. Check the listener configuration

If you confirm that the listener has been started, but the problem of being unable to listen to the program still occurs, you need to check whether the listener configuration is correct. You can check whether the listener can successfully listen to the database instance by running the command lsnrctl services.

If the listener is configured incorrectly, the listener needs to be reconfigured. It can be configured by modifying the listener configuration file listener.ora.

3. Check the firewall rules

The inability to monitor the program may also be related to the firewall rules. The firewall blocks communication between the database and the application, preventing the database from starting properly. Therefore, when there is a problem that the program cannot be monitored, you can first check whether the firewall rules are correct.

If the firewall rules are incorrect, you need to modify the relevant rules and restart the firewall. At the same time, you also need to ensure that the communication between the database server and the application server is normal.

4. Check the listener port

If the listener port conflicts, it will also cause an error that the program cannot be listened to. Therefore, you need to check whether the listener port is set correctly. The port number can be modified by modifying the listener configuration file listener.ora.

5. Check Oracle service

Finally, you need to check whether the Oracle service is started. You can view the status of Oracle services by running the command services.msc. If the service is not started, you need to start the service manually.

Summary

The failure to listen to the program is one of the common Oracle database errors. When encountering this problem, you can troubleshoot and solve it from many aspects such as whether the listener is started, listener configuration, firewall rules, listener port, Oracle service, etc. By checking the above points, the problem of being unable to monitor the program can be solved in many cases.

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