How to solve the issue of Oracle TNS not being able to listen on port 1521?

If Oracle TNS is unable to listen on port 1521, it may be due to issues such as firewall settings, network problems, or misconfiguration of the Oracle service. Here are some possible solutions:

1. Check the firewall settings: ensure that the firewall allows traffic through port 1521. You can try disabling the firewall or adding an exception rule to allow Oracle TNS to listen on port 1521.
2. Check the network connection: Make sure the network connection is working properly, you can try using the telnet command to test if port 1521 is available.
3. Check Oracle service configuration: Make sure the Oracle database instance is properly configured with the TNS listener, and that the correct port is specified in the listener configuration file (listener.ora).
4. Restart the Oracle services: Try restarting the Oracle database service and TNS listener service to see if it resolves the issue.
5. Check the port occupancy situation: It is possible that another application is occupying port 1521, causing Oracle to be unable to listen. You can use the netstat command or other network tools to check the port occupancy situation and try to release the program occupying the port.

If the above methods do not solve the problem, we suggest you contact Oracle technical support or your network administrator for further assistance.