How to troubleshoot connection refused when installing PHP on CentOS?

If you encounter a connection refused issue while installing PHP on CentOS, it could be due to firewall, network configuration, or PHP configuration issues. Here are some possible solutions:

1. Check firewall settings: Begin by examining the firewall settings on CentOS to ensure that ports 80 (HTTP) and 443 (HTTPS) are open. You can use the following command to view the firewall settings: sudo firewall-cmd –list-all.
2. Check network configuration: Make sure the CentOS server’s network configuration is correct, including the correct IP address, subnet mask, gateway, etc. You can use the following commands to view network configuration: ifconfig or ip addr.
3. Check PHP configuration: Make sure PHP configuration is correct, including correct database connection information, host address, etc. You can verify the relevant configuration options in the PHP configuration file (such as php.ini).
4. Check the service status: Ensure that relevant services (such as Apache, MySQL, etc.) have been successfully started and are running. You can use the following commands to check the service status: sudo systemctl status apache2 or sudo systemctl status mysql.
5. Restarting services: If the previous methods did not solve the issue, you can try restarting the relevant services, such as: sudo systemctl restart apache2 or sudo systemctl restart mysql.

If none of the above methods can solve the connection refused issue, it is recommended to check the system logs and service logs for more detailed error information, and further troubleshoot and resolve the issue based on the error messages.