- Check SQL Server Configuration: Ensure SQL Server is configured to accept remote connections. Use SQL Server Configuration Manager to check this:
- Open SQL Server Configuration Manager.
- Navigate to SQL Server Network Configuration -> Protocols for [YourInstance].
- Ensure TCP/IP is enabled.
- Verify SQL Server is Running: Confirm that the SQL Server instance is running. You can do this by connecting locally using a tool like SQL Server Management Studio (SSMS).
- Check Firewall Settings: Ensure the firewall on the machine where SQL Server is installed is not blocking connections. You might need to allow traffic on the port SQL Server is using (default is 1433 for TCP/IP).
- For Windows Firewall, you can add an inbound rule to allow TCP traffic on port 1433.
- Review SQL Server Error Logs: Look at the SQL Server error logs to see if there are any entries related to failed login attempts or connections. This can provide clues as to why the connection was rejected.
- You can view the logs using SSMS, under Management -> SQL Server Logs.
- Check SQL Server Authentication Mode: Make sure SQL Server is in the correct authentication mode (Windows or SQL Server Authentication) that matches your connection string from Postgres. If you need to change the authentication mode:
- Connect to SQL Server using SSMS.
- Right-click the server, and go to Properties -> Security.
- Select the desired authentication mode and restart the SQL Server service.
- Verify SQL Server Login and Permissions: Ensure the login you're using from the Postgres side exists in SQL Server and has the correct permissions. If unsure, you can create a new login for testing:
- ```sqlCREATE LOGIN [YourLogin] WITH PASSWORD = 'YourPassword';
- ```sql
USE [YourDatabase];
CREATE USER [YourUser] FOR LOGIN [YourLogin];
GRANT SELECT ON [YourTable] TO [YourUser];
- Check the Connection String: Make sure the connection string used from Postgres (in the Foreign Data Wrapper or relevant extension) is correctly formatted and includes the correct server name, instance (if any), database name, login, and password.
- Test Network Connectivity: Use
telnet or Test-NetConnection in PowerShell to verify network connectivity to the SQL Server port from the machine where Postgres is running.- ```powershellTest-NetConnection -ComputerName YourSqlServer -Port 1433
- If the test fails, there might be a network issue preventing connectivity.
9. **Review Postgres Logs**: Check the Postgres logs for any additional information on the connection attempt. It might provide more context on why the connection was rejected.
10. **Restart Services**: If applicable and safe to do so, restart the SQL Server and Postgres services to ensure all settings are freshly applied and there are no transient issues.
- For SQL Server, you can use SQL Server Configuration Manager or services.msc.
- For Postgres, the command varies by installation, but for many systems, it's:
```bash
sudo systemctl restart postgresql
