How To 

How To Change Default Internet Connection Sharing IP Address Range

When Internet Connection Sharing (ICS) is enabled on an NIC that is connected to the direct Internet line, the second NIC automatically gets the IP address and subnet mask. Since the first IP address of the address range is set on the second NIC of the computer, the other client computers receive the other IP addresses from the same range, for example, and so on.

In earlier versions of Microsoft Windows, such as Windows 98 or Windows 2000, the IP address range was with the same subnet mask. This IP address range was probably changed in order to avoid the IP address conflicts that used to occur when any router with the identical IP address range (default range in most routers) was placed anywhere in the network.

In your case, if you do not wish to have the new range of IP addresses, i.e. 192.168.137.x, while enabling the Internet Connection Sharing on your computer, Windows 7 and all other upper versions of Microsoft Windows allow you to modify the default range by editing the Windows registry.

Warning: Modifying Windows registry incorrectly might make your system unstable permanently. In case you are not well versed with the Windows architecture and/or you are not sure what you are doing, do NOT continue. If you still wish to continue, make sure that you follow the instructions exactly the way they are given in this tutorial. No one else but you and only you will be responsible if you fail to follow the instructions correctly given in this tutorial and end up having a completely unstable operating system.

Here is how you can modify the default IP address range that is assigned to the second NIC when the Internet Connection Sharing is enabled on the LAN card that is connected to the direct Internet line:

    ■Log on to the computer with the administrator account.

    ■After logging on, press the Windows + R keys simultaneously to initialize the Run command box.

    ■In the available field of the opened box, type the REGEDIT command and hit Enter key.

    ■On the displayed User Account Control confirmation box, click the Yes button to provide your consent to continue.

    ■On the opened Registry Editor window, from the left pane, go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SharedAccess\Parameters.

    ■Once the Parameters container is selected from the left pane, in the right pane, double-click the ScopeAddress and StandaloneDHCPAddress individually.

    ■On the opened Edit String box, modify the IP address range of your choice in the Value data field.

    ■Once done, click OK to close the box.

    ■Finally close the Registry Editor window.

    ■Restart the computer in order to allow the changes to take effect.