Imagine you need to share some files with a friend or with a colleague while in a meeting and do not have any network means to connect to! You can set up a temporary wireless network between two or more computers running Windows 7 or Vista assuming that both computers are equipped with a wireless interface and are within 9 meters of each other. An ad hoc wireless network is quickly set up as you can see from the following steps:
A small wired network may consist of an 8 or 5 port network switch which connects all computers together, and one Windows 7 machine running ICS bridging the network and the Internet connection through the ISP cable or dial-up modem as shown below. Internal computers can obtain their IPv4 configuration from the ICS machine while the ICS machine get its configuration from the modem which in turn is configured by the ISP. Some ISPs may provide you with a combined modem and router where you may omit the ICS computer as this role will be provided by the modem/router device.
You can view the IP configuration of your computer by using either the command-line tools Ipconfig or Netsh, or by using the Network and Sharing Center. The command-line tools display your computers’ network adapters IP settings including IPv4 and IPv6 addresses, subnet masks and the default gateway.
An IP address identifies a computer in a network and hence, each computer must have a unique address within the same network. Private IP addresses are used for internal networks while public addresses are used for the Internet. Since there are not enough public IP addresses to be allocated for every internal device, we use private addresses internally and use NAT to translate these addresses to a public address. An organization or individual that needs Internet access is allocated one or more public IP addresses through various agencies worldwide that are responsible for the distribution of public IP addresses.
Sharing the Internet connection over windows 7 requires one computer called the host that is connected to the Internet and to the rest of the computers on the internal network (LAN). Then the computers on the network connect to the Internet via the host computer. The host computer Internet connection can be wireless, modem (Ethernet or USB), 3G card or any similar device. To use ICS make sure that the LAN connection on each computer is configured to get an IP address automatically. This includes the LAN connection of the host computer.