ERROR – SQL Server Login Failed, Error 11001

Question

We have an application that uses MSDE as its ‘Back-end’. 
It has been working fine for years.  We have however had to recently re-build the Operating System on our own Server that it was running on. 
Original O/S Environment
We used Windows Server 2008 r2, using
Hyper-V to run Windows Server 2003 so that we can use
MSDE to run our application. 
We do not want to change to later versions of SQL Server Express as they no-longer support Replication.
NEW O/S Environment
When we re-built the Server we went for Windows Server 2008 r2, using
Hyper-V to run Windows 7 Enterprise so that we can use
MSDE to run our application. 
We have used this setup many times before and know that MSDE runs quite happily under Windows 7. 
Servers have been renamed
The real Windows Server 2008 r2 machine used to be called FILESERVER. 
It is now called FILE-SERVER.
The virtual machine running our application was originally called GEMSERVER. 
It is now called GEM-SERVER. 
What’s happening on the Server
The application is running fine.  We can access the underlying MDSE Database with SQL Server 2005 Management Studio Express without problem.
 We can build a test ODBC Data Source and connect to the ‘SQL Server’ Database, again without problems. 
What’s happening on the Client PC
The application does not connect.  I get:
     An error occurred while connecting.
     [DBNETLIB]ConnectionOpen (Connect())SQL Server does not exist
     or access denied.
When I build a ODBC Data Source to test the Connection I get:
Microsoft SQL Server Login
Connection failed:
     SQLState: '01000'
     SQL Server Error: 11001
     [Microsoft][ODBC SQL Server Driver][TCP/IP Sockets]ConnectionOpen
     (Connect()).
     Connection failed:
     SQLState: '08001'
     SQL Server Error: 6
     [Microsoft][ODBC SQL Server Driver][TCP/IP Sockets]Specified SQL
     server not found
I can Ping GEM-SERVER from the Client PC without problems. 
I have disabled Firewalls an Anti-Virus Software on both the GEM-SERVER and the Client PC – to no avail. 
I’ve tried connecting with:
Named Pipes,
TCP/IP,
IP Address of GEM-SERVER – 192.168.16.122,
Using Specific Port 1433 in connection.
NONE of it worked.  L
ANYBODY any ideas what to try next?

Answer 1

Here's the solution that we came up with to our own problem:
This problem was actually caused by a bug in our own Application. 
For some reason when we restored our MDSE Database the correct SQL Server Access Protocols were not setup correctly.  (It is designed to handle these setup issues for us and has done so previously.) 
We still have to determine why it happened and rectify the problem within our Software. 
However to correct the problem with our own 'Server' we had to manually:
Run netsvrcn.exe using command prompt as an Administrator on the ‘Server’ running the MSDE Database,
Enable TCP and NAMED PIPES protocol
Restart SQL Server instance
Exclude the ports SQL Server normally listens on, from the firewall using ‘Windows Firewall Advanced Security’ for both in-bound and out-bound rules:
1433 TCP port
1434 UDP port
We then tested the ODBC connection from client machine and found that it worked fine, as indeed did our application.
However we still have a residual problem. 
For we cannot connect to our Server called GEM-SERVER using GEM-SERVER\GEMSQLSRVR we have had to use 192.168.16.122\GEMSQLSRVR. 
We are not sure why.  We obviously wish to use the machine’s name rather than its IP Address, as its IP Address is dynamically assigned by a DHCP server so may change in future. 
Do I need to raise this remaining problem as a separate issue?