Description of Internet Connection Sharing

This article describes Internet Connection Sharing (ICS). Note that this article is for informational use only, and because of this, it may not contain troubleshooting information.

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ICS provides networked computers with the ability to share a single connection to the Internet.

If you have multiple computers, you can use ICS to allow you and others on your local area network (LAN) to perform different tasks simultaneously. For example, one person can send and receive e-mail messages, while another person downloads a file, and another person browses the Internet. You can also gain access to your corporate e-mail accounts from a client computer while others on your LAN cannot. You can use Web-enabled programs (such as downloading updates) as well as Microsoft NetMeeting and other video conferencing programs.

Internet Connection Sharing Capabilities

• Multiple users can gain access to the Internet through a single connection by using Dial-Up Networking and local networking.
• Connected devices receive transparent network configuration by using Domain Name System (DNS) and Dynamic Host Configuration Protocol (DHCP) to resolve Internet names.
• Any IP-attached device can connect, including older Windows-based clients, non-Windows-based clients, Microsoft Windows 98-based clients, and Microsoft Windows 2000-based clients, with no additional client software required.
• Connected devices and software have comprehensive protocol support. For example, you can play Internet games without additional configuration, or you can use Point-to-Point Tunneling Protocol (PPTP) and Virtual Private Networking (VPN) to gain access to your corporate network.

Windows Support for Connection Sharing

To connect multiple computers to the Internet through a single Internet connection, one computer must be running Windows 98 Second Edition, Windows 2000, or Windows Millennium Edition (Me) with Internet Connection Sharing installed. Other computers on your LAN can then gain access to the Internet through the connection on the computer with Internet Connection Sharing.

NOTE: ICS is a built-in feature of Windows 98 Second Edition, Windows 2000, and Windows Me, and is not a component available for download.

Internet Connection Sharing Components

• DHCP Allocator - A simplified DHCP service that assigns the IP address, gateway, and name server on the local network.
• DNS Proxy - Resolves names on behalf of local network clients and forwards queries.
• Network Address Translation (NAT) - Maps a set of private addresses to a set of public addresses. NAT tracks private-source IP addresses and public-destination IP addresses for outbound flows. It changes the IP address information and edits the required IP header information dynamically.
• Auto-dial - Automatically dials connections.
• Application programming interfaces (APIs) - For configuration, status, and dial control for programs.
  

Setting Up a Network with Internet Connect Sharing

Your ICS network is a type of local area network that relies on a single computer called a gateway, through which all other computers and TCP/IP-capable devices connect to the Internet.

The hardware and software needed to set up a home network includes:

• A primary computer, called a gateway, that provides network connectivity to the Internet. This computer must be running Windows 98 Second Edition, Windows 2000, or Windows Me with Internet Connection Sharing enabled.
• One or more computers running Windows 95, Windows 98, Microsoft Windows NT 4.0, Windows 2000, or other TCP-IP enabled client software.
• Devices that are capable of connecting to the Internet.
• A network connection device for each computer.
• Cabling and hubs, depending on the type of connection devices you use.
• A single modem (or an ISDN or ADSL line) for the entire network.
• Internet browser software and TCP/IP drivers installed on each device that shares the connection.

You can enable Internet Connection Sharing by using the Add/Remove Programs tool in Windows 98 Second Edition or Windows Me:

1. Click Start, point to Settings, click Control Panel, and then double-click Add/Remove Programs.
2. On the Windows Setup tab, double-click Internet Tools.
3. Click to select the Internet Connection Sharing check box, and then click OK.
4. Click OK, and then follow the instructions on the screen to run the Internet Connection Sharing wizard.

For additional information about ICS, click the article number below to view the article in the Microsoft Knowledge Base: For additional information about troubleshooting ICS issues, click the article number below to view the article in the Microsoft Knowledge Base: For additional information about troubleshooting automatic dialing issues with ICS, click the article number below to view the article in the Microsoft Knowledge Base: For additional information about disabling ICS, click the article number below to view the article in the Microsoft Knowledge Base: For additional information about problems with your computer restarting before the Internet Connection Sharing Wizard finishes, or for information about uninstalling and reinstalling ICS, click the article number below to view the article in the Microsoft Knowledge Base: For additional information about problems setting up ICS, click the article number below to view the article in the Microsoft Knowledge Base: For additional information about ICS and TCP/IP requirements, click the article number below to view the article in the Microsoft Knowledge Base: