NetDDE Connections Fail When "Logon to" Restrictions Apply

• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

SYMPTOMS

You are prompted for a password when connecting to a Windows NT computer while using a network dynamic data exchange (DDE) application.

CAUSE

"Logon to" restrictions are implemented such that user A can only log on to workstation A. User B logs on to workstation B, but no "Logon to" restrictions are placed on this user. A network DDE application is then started on both workstations. When workstation A attempts to dial workstation B through the network DDE application, User A is prompted for a password. If any valid non-administrative user and password is used, the connection fails with an "Invalid Password" pop-up error message.

When the network DDE client connects to the network DDE server, the server will impersonate the client. Because of this security restriction, the server portion of the network DDE application is responding with the password dialog box.

RESOLUTION

Remove "Logon To" account restrictions for the user account that originates the connection.

-or–

Add netdde to the list of workstations the user can log on from.

-or-

From the originating computer, perform the following steps:

   1. Use the Domain Administrator's account.

   2. Use the answering computer's Administrator account.

   3. Enable the domain Guest account and use it to originate the
      connection.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows NT versions 3.51 and 4.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.