You establish a dial-up connection on a Windows Vista-based computer by using USB modem device. Then, you put the computer into standby (the S3 power state). After you resume the computer from standby, you cannot establish a new connection, and you may receive the following error message:

Failed to connect to ConnectionName

Additionally, after you receive the error message, the following error may be logged in the Application log:

Log Name: Application
Source: RasClient
Event ID: 20227
Level: Error
Description:
CoID={XXXXXXXX-XXXX-XXXX-XXXXXXXXXXXXXXXXX}: The user UserName dialed a connection named ConnectionName which has failed. The error code returned on failure is 633.

When you try to put a Windows Vista-based computer to sleep while a dial-up network connection is active, the computer may crash. Additionally, you receive a Stop error message that resembles the following:

STOP: 0×0000009F (parameter1, parameter2, parameter3, parameter4)
DRIVER_POWER_STATE_FAILURE

This issue occurs even if you have installed hotfix 931671 on the computer.

Consider the following scenario:

• On a Windows Vista-based computer, you establish a dial-up connection to connect to the Internet.
• You establish a virtual private network (VPN) connection through a dial-up connection.

In this scenario, the VPN credentials are not cached the first time that the VPN connection is established.

When you use a dial-up Internet service provider (ISP) in Windows Vista, the Auto Disconnect dialog box may appear when you close Windows Internet Explorer 7. The Auto Disconnect feature closes the connection to the ISP after a designated period of inactivity or after the connection is no longer needed. However, the Auto Disconnect dialog box may automatically disappear after several seconds or after several minutes. Because of this problem, it may not be obvious that you are still connected to the dial-up ISP.

When you wake a Windows Vista-based computer from sleep or from hibernation, a dial-up connection may appear to be still connected to the Internet even though the connection is not active. When this problem occurs, the Network Center correctly shows that the dial-up connection is inactive.

This problem may occur on some computers if you put the computer to sleep or into hibernation when the dial-up connection is still connected to the Internet, and then you wake the computer. In this scenario, the network icon in the notification area may indicate that the connection is active. However, the dial-up connection does not work.

This problem can occur in some hardware configurations if the computer uses an external modem or a PCMCIA modem for the dial-up connection.

On a Windows Vista-based computer, you try to connect to a network by using a dial-up connection in Windows Internet Explorer 7. However, you may receive an error message that resembles the following:

Cannot write to the telephone book.
Error 624 : Telephone book file cannot be updated.

The dial-up connection attempt is unsuccessful.

You successfully establish a dial-up connection in Windows Vista to another computer or to the Internet. However, the IP address of the default gateway for the connection is 0.0.0.0. For example, when you run the ipconfig command at the command prompt, the default gateway appears as 0.0.0.0.

You do not experience this behavior in Microsoft Windows XP or in other earlier versions of the Windows operating system.