Quick answer: A SQL Server connection string tells your application where the database is and how to authenticate. For SQL authentication it looks like: Server=myserver,1433;Database=mydb;User Id=appuser;Password=secret;. For Windows authentication, replace the credentials with Integrated Security=true.
Server=203.0.113.25,1433;Database=YourDatabase;User Id=appuser;Password=StrongPass123!;
The comma before 1433 specifies the port. Use this style when the app connects with a SQL login.
Server=YOURSERVER\SQLEXPRESS;Database=YourDatabase;Integrated Security=true;
This uses the current Windows account and needs no password in the string.
For connections over a network, add encryption:
Encrypt=True;TrustServerCertificate=True;
Use TrustServerCertificate only where a fully trusted certificate is not installed.
Why do I get a "server not found" error?
Usually the server name or port is wrong, TCP/IP is disabled, or the firewall blocks the port. Confirm the instance name and that 1433 is open.
Named instance vs port?
Use Server=host\instance for a named instance, or host,port when connecting by port number.
Managed SQL Server on a SoftSys managed Windows VPS is configured for secure application connections out of the box.
