Unless you are running Webmin on a system that is never connected to any other network, it is a wise idea to restrict which client network addresses are allowed to log in.
To restrict the IP addresses and networks from which Webmin will accept connections, follow these steps:
Step 1 : In the Webmin category, click on the icon for the Webmin Configuration module.
Step 2 : Click on the icon for IP Access Control
Step 3 : Select the option Only allow from listed addresses, and enter the IP addresses of client systems in the text box from which you will allow access.
If you want to allow access from an entire IP network, enter the address of the network with 0 for the final octet. For example, if you wanted to allow all clients with IP addresses from 192.168.1.0 up to 192.168.0.255, you would enter 192.168.1.0.
Step 4 : When done, click the Save button to apply your changes.