I'm trying to connect to a Microsoft SQL Server 2008 Express edition over the internet. Connecting to the server over LAN works just fine. I have opened port 1433 on the firewall and set the appropriate firewall-rules on the Windows-7 machine.
A portscan also tells me that "xxx.xxx.xxx.xxx is responding on port 1433 (ms-sql-s)."
Services (Server and Browser) are running and "Allow remote connections to this server" in the server settings is also enabled.
But a connection just doesn't want to work:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections.
More information about the network:
We have a Windows 7 machine functioning as our SQL-Server and this server is directly connected to a Netgear ProSafe Firewall which then connects our server to the internet.
Both ports 1433 and 1434 are opened and forwarded to 10.9.0.1.
netstat -noab | find /i "1433" TCP 0.0.0.0:1433 0.0.0.0:0 LISTENING 3884 TCP 10.9.0.1:1433 10.9.0.1:51048 ESTABLISHED 3884 TCP 10.9.0.1:51047 10.9.0.1:1433 TIME_WAIT 0 TCP 10.9.0.1:51048 10.9.0.1:1433 ESTABLISHED 2296 TCP [::]:1433 [::]:0 LISTENING 3884