Dec 4, 2010

ICS(Internet Connection Sharing)

 

Using ICS (Internet Connection Sharing) in Windows 7

If you want to share one Internet connection among several computers, you have two options:
·         Use Internet Connection Sharing (ICS).
·         Use a router.
For information about using a router, see Setting up a home network.

How does ICS work?

First, you need one computer, called the host computer, that is connected to the Internet and that has a separate connection to the other computers on your network. You enable ICS on the Internet connection. The other computers on your network then connect to the host computer, and from there to the Internet through the host computer's shared Internet connection.

A network using Internet Connection Sharing (ICS)

Enabling ICS

To enable ICS, on your host computer:
1.      Open Network Connections by clicking the Start buttonPicture of the Start button, clicking Control Panel, clicking Network and Internet, clicking Network and Sharing Center, and then clicking Manage network connections.
2.      Right-click the connection that you want to share, and then click Properties. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
3.      Click the Sharing tab, and then select the Allow other network users to connect through this computer’s Internet connection check box.

Note

The Sharing tab will not be available if you have only one network connection.
4.      If desired, you can also select the Allow other network users to control or disable the shared Internet connection check box.
5.      Optionally, to allow other network users to use services running on your network, click Settings and select the services you want to allow.
When you enable ICS, your local area network (LAN) connection gets a new static IP address and configuration, so you'll need to reestablish any TCP/IP connections between your host computer and the other network computers.
To test your network and Internet connection, see if you can share files between computers and make sure each computer can reach a website.

Configure TCP/IP

To use ICS, make sure the local area network (LAN) connection on each network computer is configured to get an IP address automatically. To do this:
1.      Open Network Connections by clicking the Start button Picture of the Start button, clicking Control Panel, clicking Network and Internet, clicking Network and Sharing Center, and then clicking Manage network connections.
2.      Right-click the LAN connection, and then click Properties. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
3.      Click Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6), and then click Properties.
4.      Click Obtain an IP address automatically or Obtain an IPv6 address automatically.
The Internet options on your network computers should also be configured for ICS. For more information, see Change Internet settings for ICS (Internet Connection Sharing).
Do not use ICS on a network with domain controllers, DNS servers, gateways, or DHCP servers. And don't use ICS on systems configured for static IP addresses.

ICS and VPN connections

If you create a virtual private network (VPN) connection on your host computer to a corporate network and then enable ICS on that connection, all Internet traffic is routed to the corporate network and all of the computers on your home network can access the corporate network. If you don't enable ICS on the VPN connection, other computers will not have access to the Internet or corporate network while the VPN connection is active on the host computer.

ICS and ad hoc networks

If you share your Internet connection on an ad hoc network, ICS will be disabled if:
·         You disconnect from the ad hoc network.
·         You create a new ad hoc network without disconnecting from the ad hoc network for which you enabled ICS.
·         You log off and then log back on (without disconnecting from the ad hoc network).



How to use Internet Connection Sharing in XP
To use Internet Connection Sharing to share your Internet connection, the host computer must have one network adapter that is configured to connect to the internal network, and one network adapter or modem that is configured to connect to the Internet.


On the host computer
On the host computer, follow these steps to share the Internet connection:
  1. Log on to the host computer as Administrator or as Owner.
  2. Click Start, and then click Control Panel.
  3. Click Network and Internet Connections.
  4. Click Network Connections.
  5. Right-click the connection that you use to connect to the Internet. For example, if you connect to the Internet by using a modem, right-click the connection that you want under Dial-up.
  6. Click Properties.
  7. Click the Advanced tab.
  8. Under Internet Connection Sharing, select the Allow other network users to connect through this computer's Internet connection check box.
  9. If you are sharing a dial-up Internet connection, select the Establish a dial-up connection whenever a computer on my network attempts to access the Internet check box if you want to permit your computer to automatically connect to the Internet.
  10. Click OK. You receive the following message:
When Internet Connection Sharing is enabled, your LAN adapter will be set to use IP
address 192.168.0.1. Your computer may lose connectivity with other computers on
your network. If these other computers have static IP addresses, it is a good idea to set them
to obtain their IP addresses automatically. Are you sure you want to enable Internet
Connection Sharing?
  1. Click Yes.
The connection to the Internet is shared to other computers on the local area network (LAN). The network adapter that is connected to the LAN is configured with a static IP address of 192.168.0.1 and a subnet mask of 255.255.255.0






On the client computer
To connect to the Internet by using the shared connection, you must confirm the LAN adapter IP configuration, and then configure the client computer. To confirm the LAN adapter IP configuration, follow these steps:
  1. Log on to the client computer as Administrator or as Owner.
  2. Click Start, and then click Control Panel.
  3. Click Network and Internet Connections.
  4. Click Network Connections.
  5. Right-click Local Area Connection, and then click Properties.
  6. Click the General tab, click Internet Protocol (TCP/IP) in the This connection uses the following items list, and then click Properties.
  7. In the Internet Protocol (TCP/IP) Properties dialog box, click Obtain an IP address automatically (if it is not already selected), and then click OK.

    Note You can also assign a unique static IP address in the range of 192.168.0.2 to 192.168.0.254. For example, you can assign the following static IP address, subnet mask, and default gateway:
8.          IP Address      192.168.0.2
9.          Subnet mask     255.255.255.0
10.       Default gateway 192.168.0.1
                                                                                     
  1. In the Local Area Connection Properties dialog box, click OK.
  2. Quit Control Panel.


Click Start, and then click Control Panel.
  1. Click Network and Internet Connections.
  2. Click Internet Options.
  3. In the Internet Properties dialog box, click the Connections tab.
  4. Click the Setup button.

    The New Connection Wizard starts.
  5. On the Welcome to the New Connection Wizard page, click Next.
  6. Click Connect to the Internet, and then click Next.
  7. Click Set up my connection manually, and then click Next.
  8. Click Connect using a broadband connection that is always on, and then click Next.
  9. On the Completing the New Connection Wizard page, click Finish.
  10. Quit Control Panel.
When you now start Microsoft Internet Explorer, the client computer will try to connect to the Internet by using the host computer's shared Internet connection.






Troubleshooting
When you turn on Internet Connection Sharing on the host computer, the host computer's LAN adapter is automatically assigned the IP address of 192.168.0.1. Therefore, one of the following situations may occur:
  • IP address conflict
    Each computer on the LAN must have a unique IP address. If more than one computer has the same IP address, an IP conflict occurs, and one of the network adapters turns off until the conflict is resolved. To resolve this conflict, configure the client computer to automatically obtain an IP address, or assign it a unique IP address.
  • Loss of network connectivity
    If your network is configured with a different IP address range than Internet Connection Sharing uses, you will lose network connectivity with the host computer. To resolve this issue, configure the client computers to automatically obtain an IP address, or assign each client computer a unique IP address in the range of 192.168.0.2 to 192.168.0.254.