Sharing an Internet Connection

You may have a home or office network and also have a requirement to connect to the internet from more than one of these computers. One way to do it would be to provide each computer with their own modem and phone line and allow each to connect separately to the internet. This is definitely not the best solution.

A better solution is to provide a dial up connection to the internet from only one computer on the network and share that connection across your local network. So how do we do this? Well, if your computer is running Linux, Windows 98SE or ME, or Windows 2000 or XP then you already have the necessary software to use with that computer to allow its internet connection with the rest of the network. If you don't have a computer running one of these operating systems then you can achieve the same result in one of two ways. Firstly, you could purchase a third party software product that runs on your operating system that handles internet sharing for you, or secondly (which you may prefer to go with even if your operating system includes the necessary software), you can purchase network hardware that allows your modem (or other internet connection) to be attached directly to your network hub and which makes the internet accessible to all computers on the network.

Whichever method that you go with, the computer (or hardware device) that provides the internet connection acts as a proxy server for the other computers on the network. When you are configuring the various computers on your network to share the internet access you may need the IP address of this proxy server to configure the internet access on the other computers.

For the purpose of describing how to set up your network to allow internet sharing, I will assume that the computer that will be used as the proxy server is running Windows 98SE. If you're running a different operating system or have purchased software to share the connection then the setup process should be similar but the options may not be in the same place.

While internet sharing is provided as part of Windows 98SE (it wasn't in Windows 98), this software is not installed by default when you first install the operating system so chances are you will have to install it. To do this go via the Start menu into Settings and then to Control Panel. Next select Add/Remove Programs and then click on the Windows Setup tab. You may have to wait while windows works out what components are already installed. Next double click on Internet Tools to display the list of windows components that handle your internet access. The one that you are looking for is called Internet Connection Sharing and it's the one at the top of the list. Ensure that the box next to this entry is checked and then press the OK button. Once the internet tool window disappears press the OK button at the bottom of the Add/Remove Programs dialog to start the install process. Follow the prompts to install this component. During the process you will be asked if you want to create an "Internet Connection Sharing Client" disk. You can bypass this step if you are going to configure the other computers manually. Once the component is installed you will need to restart the computer.

If you only had the one computer accessing the internet then your firewall software should have been configured to not allow the internet to access the other computers on your network. With internet connection sharing installed you may need to lower the settings of any firewall software that you have on that computer so as to allow communications between the other computers on the network and the internet.

You now need to set up each of the other computers on your network so that they will use the proxy server to access the internet. To do this you can either use the disk that was created when you installed the connection sharing software (provided that the computer is running Windows 95 or 98) or alternatively you can manually update each computer (regardless of which operating system it's running. The instructions that Microsoft provide on how to set up Windows 95 or 98 manually are as follows. You may need to adapt these instructions slightly for other operating systems.

  1. In the Control Panel, double-click the Network icon.
  2. In the list of network components, click TCP/IP associated with your network adapter, and then click Properties.
  3. Select the "Obtain an IP address automatically" check box.
  4. Click the WINS Configuration tab, and then select the check box next to "Use DHCP for WINS Resolution".
  5. Click the Gateway tab, and then remove any installed gateways if any are listed.
  6. Click the DNS Configuration tab, and then select the check box next to "Disable DNS".
  7. Click OK to accept the new TCP/IP settings
  8. Click OK to update your new network configuration. The computer will need to reboot.

This should enable you to share the dial up internet connection with the other computers on your local area network. If you prefer not to use DHCP then you can install the dhcp_off.inf file supplied with Internet Connection Sharing to turn this option off. If you do this then you will need to assign IP addresses manually to all computers on your system.


This article written by Stephen Chapman, Felgall Pty Ltd.

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