When more than one network connection is available, Windows uses the one with the lowest metric value. By default, it automatically assigns a metric value based on the network connection's rated speed. See An explanation of the Automatic Metric feature for Internet Protocol routes .
To force Windows to use a specific network connection, assign a metric value to each one, giving the lowest value to the desired connection:
1. Open the Network Connections folder (Start > Run > ncpa.cpl)
2. Right click the desired connection.
3. Click Properties > Internet Protocol Version 4.
4. Click Properties > Advanced.
5. Un-check "Automatic metric".
6. Enter a number between 1 and 9999 for the "Interface metric".
To force Windows to use a specific network connection, assign a metric value to each one, giving the lowest value to the desired connection:
1. Open the Network Connections folder (Start > Run > ncpa.cpl)
2. Right click the desired connection.
3. Click Properties > Internet Protocol Version 4.
4. Click Properties > Advanced.
5. Un-check "Automatic metric".
6. Enter a number between 1 and 9999 for the "Interface metric".