In order to configure the Internet Connection Sharing on your computer, the computer must have at least two network interface cards (NICs), where one NIC must be connected to the direct Internet connection, and the other NIC must be connected to a LAN switch. The LAN switch can further have multiple PCs connected to it.
The second NIC (the one which is connected to the LAN switch) on the computer must not be assigned with a static IP address, and must be configured to obtain the IP address automatically from the DHCP server. As soon as the Internet Connection Sharing is enabled on the first NIC (the one that is connected to the direct Internet line), the operating system automatically assigns an IP address to the second NIC. The IP address that is assigned to the second NIC is of 192.168.137.x range and has 255.255.255.0 subnet mask. When this happens, the second NIC starts working as a mini DHCP server and automatically starts assigning IP addresses to all the other computers that are connected to the LAN switch assuming them as the DHCP clients.
Note: While enabling the Internet Connection Sharing (ICS) on your computer, make sure that you enable the ICS on the LAN card that is directly connected to the Internet line. If you enable the ICS on the other LAN card (that is connected to the LAN switch), the ICS would not work, and none of the client computers over be able to access the Internet whatsoever.
Here is how you can configure the Internet Connection Sharing on your computer if it has multiple NICs installed in it:
- Log on to the computer using administrator account.
- After logging on, press the Windows + R keys simultaneously to initialize the Run command box.
- On the opened box, in the field, type the NCPA.CPL command and press Enter key.
- On the opened Network Connections window, right-click the icon of the NIC that is connected to the direct Internet line.
- From the displayed context menu, go to the Properties option.
- On the opened NIC properties box, go to the Sharing tab.
- On the displayed interface, check the Allow other network users to connect through this computer’s Internet connection checkbox.
- Once done, click OK to save the changes.