SME Server is a freely available, open source operating system built on GNU/Linux. It's purpose is to operate as a server and Internet gateway in small to medium workgroups, and it includes all the functionality required in such an environment. It's fully compatible with Windows, Mac, and Linux clients, and can function as a Windows domain controller if required.
As an Internet gateway it supports modem, ISDN, cable, and broadband connections, complete with firewalling features. Each service (Web, FTP, email, etc) can be individually configured as to whether it is accessible from the Internet or only locally, providing maximum control of security.
It is simple to install and administer, without requiring in-depth knowledge of Linux. All administration is performed via a Web browser, and can be done from any machine on the network. Once installed there is no need even to have a console connected to the server. Disk - 1