Webmin is a web-based interface for system administration for Linux. Using any modern web browser, you can setup user accounts, Apache, MySQL, DNS, file sharing and much more. Webmin lets you manage a system from the console or remotely.
Free & Open Source
Yes it’s both free and open source. There is no need of paying monthly fees to commercial control panels like cPanel & Plesk when you are going to host your own private websites on your private server. The important basic things that you are going to do is create email accounts, databases and edit dns etc. which can be easily be managed from webmin
Third-Party Modules Support
Numerous Webmin modules and themes have been created by independent developers, to cover functions that do not exist in the core Webmin package and to provide new user interfaces. You can search them here http://www.webmin.com/cgi-bin/search_third.cgi?modules=1 OR you can create your own custom modules that suits your needs.
Whenever your got stuck somewhere in your webmin server management or module development, you can ask for help at the community.