How to Set up and Use Internet Connection Sharing (XP)

With Internet Connection Sharing (ICS) in Windows XP, you can connect one computer to the Internet, then share the Internet service with several computers in a home or small office network. The Network Setup Wizard in Windows XP Professional will automatically provide all of the network settings you need to share one Internet connection with all the computers in the network. Each computer can use different programs such as Internet Explorer and Outlook Express as if they were directly connected to the Internet.

You shouldn't use this feature in an existing network with Windows 2000 Server domain controllers, DNS servers, gateways, DHCP servers, or a system that is configured for static IP addresses.


Enabling ICS

The ICS host computer needs two network connections. The local area network connection, will be automatically created upon installing a network adapter, connects to the computers on your home or small office network. The other connection, which uses 56k modem, ISDN, DSL, or cable modem, connects the home or small office network to the Internet. You need to ensure that ICS is enabled on the connection that has the Internet access. By doing so, the shared connection can connect your home or small office network to the Internet, and users outside your network are not at risk of receiving inappropriate addresses from your network.
When you enable ICS, the local area network connection to the home or small office network will be given a new static IP address and configuration. Consequently, TCP/IP connections established among any home or small office computer and the ICS host computer at the time of enabling ICS are lost and need to be reestablished. For example, if Internet Explorer is trying to connect to a Web site when Internet Connection Sharing is enabled, refresh the browser to reestablish the connection. You must configure client machines on your home or small office network so TCP/IP on the local area connection will be assigned an ip address automatically. Home or small office network users should configure Internet options for Internet Connection Sharing. To enable Internet Connection Sharing (ICS) Discovery and Control on Windows 98 or Windows 98 Second Edition, and Windows Millennium Edition computers, run the Network Setup Wizard from the CD or floppy disk on these computers. For ICS Discovery and Control to work on Windows 98, Windows 98 Second Edition, and Windows Millennium Edition computers, Internet Explorer version 5.0 or later version must be installed.

To enable Internet Connection Sharing on a network

you must be logged on to your computer with an owner account in order to complete this procedure.
Open Network Connections. (Click Start followed by Control Panel, and then double–click Network Connections.)

Click the local area network, dial–up, PPPoE, or VPN connection you want to share, and then, under Network Tasks, click Change settings of this connection.

On the Advanced tab section, select the Allow other network users to connect through this computer's Internet connection check box.
If you want this type of connection to dial automatically when another computer on your home or small office network attempts to access external resources, select the Establish a dial–up connection whenever a computer on my network attempts to access the Internet check box.

If you want other network users to have access to the shared Internet connection, select the Allow other network users to control or disable the shared Internet connection check box.

Below the Internet Connection Sharing selection, in Home networking connection, select any adapter that connects the computer sharing its Internet connection to the other computers on your network. The Home networking connection is only present when two or more network adapters are installed on the computer.


To configure Internet options on your client computers for Internet Connection Sharing

Open Internet Explorer. Click Start, point to All Programs, and then click Internet Explorer.)

On the Tools menu, click Internet Options.

On the Connections tab, click Never dial a connection, and then click LAN Settings.

In the Automatic configuration window, clear the Automatically detect settings and Use automatic configuration script check boxes.

In Proxy Server, clear the Use a proxy server check box.

setup Internet Connection Firewall(ICF)

How to setup Internet Connection Firewall(ICF)

Windows XP is mad about the Internet. Right from the get go during installation XP works best if you have an Internet connection available to download the latest updates and drivers. This online thread extends throughout the operating system: In the presence of features such as Windows Messenger and Remote Assistance, right through to the way the Help and Support Center draws material from Microsoft's online Knowledge Base if you have an active Internet connection.

Of course, the more time you spend online, the more vulnerable you become to attempts to hack into your computer. This is especially the case if you have an always-on cable or DSL connection. But even if you're using a dial-up connection, you are at risk.

The good news is, Windows XP comes with built-in protection for your Internet connection. It's called Internet Connection Firewall (ICF) and setting it up requires no more than a tick of a box when you create your Internet connection.

What's a firewall?

In everyday terms, a firewall is a wall built between buildings to contain the spread of fire. In computing terms, it's a program (or a piece of hardware) designed to prevent the spread of unauthorised communication between computers.

Windows XP's ICF is a software firewall. It's a pretty limited one from the average user's viewpoint because there's almost no flexibility in its operation – you just switch it on and let it protect your system as it deems best. In fact, there are options for fine tuning ICF, but they're really designed for use by system administrators, and most users will want to steer clear of these settings.

You can use ICF to protect a single computer connected to the Internet or a home network of computers connected to the Internet.

If you wish to protect your home network, the simplest method is to establish a shared connection to the Internet using Internet Connection Sharing (ICS) and then install the firewall on the ICS host computer.

Setting up a protected connection

The easiest way to activate the firewall is to use the New Connection Wizard to create an Internet connection.

If you have an always-on cable or DSL connection, your connection should be set up already, so you won't need to do this. If you have a high-speed connection which requires a password login (sometimes called a Point-to-Point over Ethernet, or PPPoE, connection) or if you use a dial-up connection with a modem, here's how to create a protected connection:

1. Click Start -> Control Panel -> Network And Internet Connections -> Setup Or Change Your Internet Connection.
2. In the Internet Properties dialog box, click Setup to open the New Connection Wizard and then click Next.
3. For Network Connection Type, choose Connect To The Internet and click Next.
4. If you already have an ISP, select Set Up My Connection Manually. You'll need to make sure you have your username, password and – for dial-up connections – the connection number from your ISP. If you don't already have an Internet Service Provider (ISP), select Choose From A List Of Internet Service Providers. This option will, in fact, close the Network Connection Wizard and direct you to the Online Services folder, where you can create a connection from a list of ISPs. The third option (Use The CD I Got From An ISP) also closes the Network Connection Wizard. If you're setting up your connection manually continue with the following steps.
5. Select your type of connection, dial-up or high-speed (broadband) from the list and click Next.
6. On the following screens, type in your ISP's name and, for dial-up connections, phone number, and click Next to proceed.
7. In the Internet Account Information screen, type in your ISP-supplied username and password (you enter the latter twice to ensure it's correct). You can tick options to make this connection the default connection (in case you have multiple ISP accounts) and the connection for all users of your computer. To activate the firewall for this connection, click Turn On Internet Connection Firewall For This Connection. Click Next and then Finish.

Switching it on and off

If you want to enable or disable ICF on an existing Internet connection:

1. Click Start -> Control Panel -> Network And Internet Connections -> Network Connections.
2. Click the connection you wish to change and select the Change Settings Of This Connection task.
3. Click the Advanced tab and click the option in the Internet Connection Firewall section.

You can also switch on ICF logging and access advanced firewall settings from this dialog. ICF logging lets you keep track of the firewall's activities by creating a text log file, which you can examine at any time.