What is ICS or Internet Connection Sharing?

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ICS or Internet Connection Sharing, allows a local network of Windows computers to  share a single Internet connection. Microsoft developed ICS as part of Windows 98 Second Edition. The feature has been included as part of all subsequent Windows releases, but it is not available as a separate installable program.

How ICS Works

ICS follows a client/server model. To set up ICS, one computer must be chosen as the server.

The designated computer must support two network interfaces, one directly connected to the Internet and the other connected to the remainder of the LAN. In a traditional home dial-up network, for example, the server computer is directly connected to the  modem.

When configured through Windows, the ICS server behaves as a  NAT router, directing messages on behalf of multiple computers. ICS incorporates a  DHCP server that allows clients to obtain their local addresses automatically rather than needing to be set manually.

How it Compares

Compared to hardware routers, ICS has the advantage of being included with the  operating system so no additional purchase is required. On the other hand, ICS lacks many of the configuration options that hardware routers possess.

Also Known As: Internet Connection Sharing, Windows ICS