Sharing an Internet connection

Advantages

If you have a local area network (two or more computers connected in a network) with one computer connected to the Internet (via a modem, using a cable, etc.), it may be useful to make the connection accessible to the other computers on the network by installing a software program that will serve as aproxy server, that is, that will give the network's computers access by proxy, by redirecting data packets.

However, the more users there are, the lower the bandwidth for each of them will be, since the users will share the bandwidth with each other. For example, if 8 people are connected to an ADSL connection at 512 Kb/s, only 64 kb/s will remain per person, or 6 or 7 kB/s per person.

There are a variety of software programs that make it possible to carry out this function, yet Window 98, Windows 2000, Windows XP and higher versions natively offer such a function.

We will now assume that the connection is already configured on the PC equipped with Internet access. This computer (PC no.1) will play the role of server (proxy) whereas the other network computers will be clients (PC no. 2, 3 and 4, etc.).

We will choose the address 192.168.0.1 for PC no. 1 that has the Internet connection (the others will respectively take the IP addresses 192.168.0.2, 192.168.0.3, 192.168.0.4, etc.).

Server in Windows XP/2000

To authorize Internet connection sharing on the host (the computer with an Internet connection), simply right-click "My network places" on the desktop, then choose Properties in the menu. Right-click your connection's icon, then choose Properties. Then click the Advanced tab and check the box Allow other network users to connect through this computer's Internet connection as well as the other two boxes. Then validate by clicking OK and close the Network connection window.

If this option is not available in the Advanced tab, you can use the network setup wizard at the bottom of the tab and specify that "This computer connects directly to the Internet. The other computers on my network connect to the Internet through this computer"!

Clients in Windows XP/2000

The next step is to configure client gateways. The gateway is the IP address of PC no. 1 that has the Internet connection, or 192.168.0.1 in our case.

In the "Internet protocol properties (TCP/IP)" window, in the "General" tab, enter 192.168.0.1 as the gateway for each of the clients. Still in the "General" tab, click "Use the following DNS server address" and enter the following information:

Preferred DNS server: 192.168.0.1
Alternate DNS server: nothing

They correspond to the primary and secondary DNS (Domain Name Servers).

Server in Windows 98

To share a computer's connection in Windows 98, you first need to install the "Internet connection sharing" service. To do so, go to Start/Settings/Control panel/Add or Remove programs/Windows setup/Internet tools then select "Internet connection sharing". Confirm by clicking "ok", then indicate the Windows 98 CD-ROM directory when the system asks for it.

Clients in Windows 98

You need to configure the clients (the other network computers) so they know that the connection is being made through the PC1. In the "Gateway" tab of the "TCP/IP properties" window, enter 192.168.0.1 as new gateway and remember to click add. In the "DNS configuration" tab, click "Enable DNS" then enter the following information:

Host: Name-of-PC1 // for all PCs (except the PC1 itself)
Domain:

In "DNS search order", enter "192.168.0.1" and click "add".

Article written by Metathesus, Eaulive and Jeff Pillou