Use authorized server administration and retain console access plus a working session. Identify the active firewall manager instead of configuring several competing tools. Record current rules, interface zones, SSH port, Webmin port and the services intended for public use.

1. Inspect the active listeners and determine which addresses they bind to. Webmin commonly uses HTTPS on TCP 10000, but use this server configured value.
2. If firewalld manages the host, open Networking > FirewallD in Webmin and select the zone actually attached to the public interface or source network. Use the matching module for another active firewall manager.
3. Add narrow permissions for required public services, such as HTTP and HTTPS. Restrict administrative access to trusted source addresses or a protected management network where practical.
4. Preserve the current SSH and Webmin management path while testing. Review IPv6 as well as IPv4 and any provider-level security rules.
5. Apply a controlled change and open a new connection from the allowed network. Also verify that a disallowed source cannot access the restricted administration listener.
6. Make the intended rule persistent using the firewall manager supported workflow and verify its state after a safe reload. Keep an inventory of the purpose and owner of each exposed service.

No. The service must be running and listening on the expected address. A firewall rule only changes whether matching network traffic is permitted.

Test the website and administration connections externally. Confirm that allowed services work and unnecessary database, management or internal service ports remain inaccessible. Check that runtime and saved rules match the intended policy.

If access fails, use the console to inspect listener, zone, source address and provider rules. Do not stop the firewall or flush every rule as a routine workaround. Restore the specific prior rule set if the change blocks required management access.

• Restricting a Webmin administrator to required modules
• Managing firewalld zones and permitted services
• Restricting Ubuntu firewall access without locking out SSH
• Applying package updates through Webmin safely

• Webmin: Firewalld
• Webmin: Webmin Configuration