troubleshooting Question

SQL Server connection problems with VPN

Avatar of James St. John
James St. JohnFlag for United States of America asked on
Microsoft SQL ServerVPNWindows Networking
2 Comments1 Solution877 ViewsLast Modified:
We have a C# .NET application written against FW 3.5 that connects to a SQL server using Windows authentication on our local network.  The systems running the app are using Windows 7 SP1 or Server 2008 R2 SP1.

To provide support to some of our clients, we sometimes have to VPN (PPTP) into THEIR network - separate DNS servers, different domain name, IP subnet completely different from ours.

Whenever we're connected to a client's VPN, we get the following exception when we launch our application: System.Data.SqlClient.SqlException: Login failed for user ''. The user is not associated with a trusted SQL Server connection.

We don't understand this.  We're attempting to connect using credentials from the local domain to a SQL server on the local subnet.  Why are we getting this error?  What can we do to eliminate the problem?

We did some additional testing.
- Windows XP: problem does NOT occur.
- Windows Server 2003: problem does NOT occur.
- Windows Vista: problem does occur.
- Windows Server 2008: problem does occur.
- Windows 7: problem does occur.
- Windows Server 2008 R2: problem does occur.

-- Jim
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