Windows XP Service Pack 3-based computers in a private network that uses Internet Connection Sharing may lose network connectivity after you change the network adapter settings of the private adapter on the Internet Connection Sharing computer

On a Windows XP Service Pack 3 (SP3)-based computer that is part of a private network, you configure Internet Connection Sharing and Windows Firewall. Then, you perform one of the following actions:

• You enable or you disable the private network adapter that is configured for Internet Connection Sharing.
• You remove and then you reconnect the network cable of the private network adapter that is configured for Internet Connection Sharing.
• You change the IP address of the private network adapter that is configured for Internet Connection Sharing.

Then, you notice that other Windows XP SP3-based computers that are configured to use Internet Connection Sharing lose network connectivity. Also, computers that are newly added to the private network cannot obtain a private IP address.

This issue occurs because Internet Connection Sharing loses the firewall port exception configurations when you change the network adapter settings on the Internet Connection Sharing host. Therefore, all the data packets from the private network are dropped.

To resolve this issue, use one of the following methods.

Method 1: Use the "net start sharedaccess" command to restart the "Windows Firewall/Internet Connection Sharing" service

1. Click Start, click Run, type cmd, and then press ENTER.
2. At the command prompt, type the following command, and then press ENTER to stop the SharedAccess service:
   sc stop sharedaccess
3. At the command prompt, type the following command, and then press ENTER to start the SharedAccess service:
   sc start sharedaccess
4. At the command prompt, type exit, and then press ENTER to close the Command Prompt window.

Method 2: Use Microsoft Management Console to restart the "Windows Firewall/Internet Connection Sharing" service

1. Click Start, click Run, type Services.msc, and then press ENTER.
2. In the details pane, locate and right-click Windows Firewall/Internet Connection Sharing (ICS), and then click Restart.
3. Close the Services snap-in.