Windows XP Internet Connection Sharing

Internet Connection Sharing (ICS) enables a Windows computer to share
its Internet connection with computers on local area networks. It's
been around since Windows 98 SE, and with the launch of Windows XP,
it's only gotten better.

Windows XP ICS has some notable advantages over the versions of ICS in Windows 98 Second Edition and Windows Me:

• It's easier to set up. There's no software to install, and it doesn't add any network components or protocols
• It's much more reliable and much less likely to cause network problems.
• You can create a Network Bridge connecting two or more local area
  networks and share the Internet connection with the computers on all of
  them. This is especially useful if your XP computer is connected to
  both a wired and wireless network.
• ICS client computers can use XP's Internet Gateway to monitor and
  control the server computer's Internet connection. If you have a
  dial-up connection, you can connect and disconnect when deciding
  whether to enable ICS.

However, XP ICS is missing some features of those earlier versions. You
can't disable the DHCP server, change the server computer's IP address,
or change the range of addresses allocated by the DHCP server.

Consider these points when deciding whether to enable ICS:

• WARNING #1 : When you enable ICS, the network adapter connected to the
  local area network is assigned a static IP address of 192.168.0.1. The
  client computers are assigned other IP addresses in the 192.168.0.x
  range. These addresses may not be compatible with an existing network
• WARNING #2 : Don't enable ICS if any computer in your network is
  configured as a domain controller, DHCP server, or DNS server. Don't
  enable it if another computer is running ICS or Network Address
  Translation (NAT).
• WARNING #3 : To enable ICS, you must be logged on as a user that is a member of the Administrators group.
• WARNING #4 : If you establish a Virtual Private Networking (VPN)
  connection while sharing a different connection, the client computers
  won't be able to access the Internet until the VPN connection is ended.

Preparing for ICS

The ICS server computer must have two network connections: one for the
Internet, and the other for the Local Area Network. The Internet connection
may be a dial-up (PPP or ISDN), cable modem, DSL, or other broadband
Ethernet connection. The LAN connection may be a wired, wireless, or
even a USB Ethernet connection. Before enabling ICS:

• Set up your Internet connection and test it so that you know you can connect to the Internet.
• Decide whether to allow client computers to control the server's
  Internet connection using the Internet Gateway. This feature is
  automatically available on clients running Windows XP. On clients
  running Windows 98, Windows 98 Second Edition, or Windows Me, you must
  run XP's Home Network Wizard to enable the gateway. If you have a
  Windows XP CD-ROM, you can run the Wizard from it. Otherwise, create a
  network setup disk containing the Wizard files.

Enabling ICS on the Server Computer

You can enable ICS either manually or by using XP's Home Network Wizard.

To use the Wizard, see the page on Server Setup Using the Network Setup
Wizard. You must use this method if you need to create a network setup
disk.