Internet Programs May Not Work as Expected with the Internet Connection Firewall Enabled

When you attempt to use certain Internet programs, you may experience any of the following symptoms:

• You cannot host a Battlezone II game, but you can join a hosted game.
• When you use ICQ99a, you cannot receive files from another ICQ client.
• You cannot host Unreal Tournament games on the Internet. Other computers on the Internet cannot connect to the Unreal Tournament server. However, another computer on your local area network (LAN) can connect.

This issue can occur if any of the following conditions exists:

• The program uses Dynamic Port Mapping. Because the port numbers on which incoming connections can be accepted change, there is no way to open specific ports on the firewall to allow communication.
• The Internet Connection Firewall (ICF) is enabled.

To work around this issue, temporarily disable the ICF by following these steps:

1. Click Start, and then click My Network Places.
2. Under Network Tasks, click View Network Connections.
3. Right-click the connection that you use for the Internet, and then click Properties.
4. Click the Advanced tab.
5. Click to clear the Protect my computer and network by limiting or preventing access to this computer from the Internet check box.

This behavior is by design.

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.