When you use a program that tries to bind to TCP network ports on a Windows-based computer, you may receive the following Winsock error message:

WSAEADDRINUSE (10048) Only one usage of each socket address (protocol/network address/port) is normally permitted.

This behavior occurs if the following conditions are true:

• Internet Connection Sharing is enabled on the computer that is running Windows.
• The program tries to connect to TCP ports in the 5001 to 5032 range.

A program opens a Winsock connection on a Windows Vista-based computer. However, the Winsock connection fails when the program calls the setsockopt function. This problem occurs if the program uses Transport Data Interface (TDI) filter drivers.

When this problem occurs, some network applications may not function correctly. For example, a user cannot use Remote Assistance to receive assistance from a remote computer. Specifically, the Remote Assistance connection is dropped shortly after the user accepts the Remote Assistance invitation. Then, the user receives the following error message:

Windows Remote Assistance is closing. An unknown error occurred so the session was disconnected.
Try restarting your session. If you continue to get this message, contact your administrator or technical support.

Additionally, the following event is logged in the Application log:

Source: Microsoft-Windows-RemoteAssistance
Date:
Event ID: 3
Task Category: None
Level: Critical
Keywords:
User:
Computer:
Description: Application will terminate, a critical error was detected in \novinterdialog.cpp Line Function OnErrorProc

In Windows Vista, a Winsock connection may fail when the program that opens the connection calls the Setsockopt function.