A Windows NT RAS client dials into a Windows NT RAS server using a user name and password that are set up for server callback with the phone number "set by caller." The server never prompts the user for a phone number to call the client back, it just authenticates and lets the user connect.

Similarly, if a Windows NT RAS client dials in to a Windows NT RAS server using a user name and password that are setup for server callback with the phone number "Preset" by the administrator, the RAS client receives the following error message:

The RAS client receives the error message after the server hangs up to call back, and the client never receives a callback from the server.

There is an option in the RAS client phone book, network settings, called "Request LCP Extensions" that MUST be checked in order for callback to work properly. This box is checked by default.

The following information on LCP Extensions is from the RAS Help file: