Network Setup

Sharing an IP Address Using a Single Computer

You can use a single computer instead of a router to share a single IP address provided by your Internet Service Provider. In this case, the computer is a host that takes or receives requests from other computers on the network and transmits them to or from the Internet. You can use a single host computer to share an IP address either by using dual network interface cards, or a software program that supports Internet connection sharing.

Before You Begin
Option 1 – Use Dual Network Interface Cards
Option 2 – Use IP-Sharing Software
Additional Information

Note: ITS does not recommend Internet Connection Sharing (ICS), as it can open up a number of security breaches in your machine. ICS is automatically installed during the Windows XP installation process if you choose to set up a home or small office network using the Network Setup Wizard. To avoid installing ICS, do not use the wizard.

If you need to run the Network Wizard in Windows XP but do not wish to enable ICS, see How to Prevent the Network Setup Wizard from Creating a Bridge in Windows XP.

Before You Begin

To use this document you must have:

• one or two network cards installed in your computer
• software or an operating system that supports IP sharing
• the installation disk for your wireless network card

Option 1 – Use Dual Network Interface Cards

In sharing configurations, the host computer has two connections – one to the Internet, and one to other computers. Typically, this requires using two network interface cards (wired or wireless NICs), or a single network interface card and a modem. One modem or NIC connects to the Internet through a phone line or cable/DSL connection, while the other NIC connects to the local area network. All traffic flowing into the first card is sent into the second card, and so it appears to originate from the second card. This solution provides simple, hardware-based firewall protection for the other computers and requires only one ISP-assigned IP address.

Setting up two network cards to share one connection is beyond the scope of this document, and how you specifically implement it depends on what other network devices you’re using (an access point, router, hub, etc.). You must also be familiar with IP addressing schemes and subnetting.

Option 2 – Use IP-Sharing Software

Windows

Several Windows software packages exist that allow one computer to share its IP address with other computers on the network. This can, in some cases, be accomplished using one network interface card, but most solutions require two network interface cards. Using two cards helps shield your network from the outside world.

WinProxy
WinGate
Nat32

Most versions of Windows also have a built-in utility called Internet Connection Sharing. The links below lead to help documents and instructions on the Microsoft Windows support websites:

Windows 98 Second Edition: Internet Connection Sharing
Windows XP: Internet Connection Sharing, How-To Guide
Windows Me: Internet Connection Sharing
Windows 98 and Me: Allowing Macintosh Clients to use Internet Connection Sharing
Windows (all): Troubleshooting Internet Connection Sharing

Note: If you have a Windows XP computer, Microsoft recommends designating it as the computer that is sharing its Internet connection. Click Start > Help and Support and then search for “Steps for creating a home or small office network” to view a checklist for setting up a network between Windows 98, 2000, Millennium, and XP computers.

Macintosh

You can share an AirPort connection or install an AirPort Software Base Station software on a Macintosh system running OS 9. Several third-party utilities also exist for Internet connection sharing on a Macintosh.

IPNetRouter
Surf Doubler

Linux

With in-depth configuration, Linux can be configured to allow a Linux-based computer to share its Internet connection with other computers on the network.

Using Linux as a Broadband Router
Coyote Linux
Linux IP Masquerade: How-To Guide

Pocket PC 2002

Microsoft Pocket PC 2002 supports Internet Connection Sharing, as well as application sharing between Windows XP desktops and Pocket PC-enabled handheld devices.

Use Your Handheld PC or Pocket PC device as a Mobile Terminal

This entry was posted on Saturday, April 21st, 2007 at 9:21 pm and is filed under Windows. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.