.Net Core Linux Container Won't Connect to SQL Server Using SQL Authentication

Question

A .Net Core 2.2 application running in a Linux Docker container fails to authenticate to SQL Server on a different machine using SQL Authentication. The error message is:

Cannot authenticate using Kerberos. Ensure Kerberos has been initialized on the client with 'kinit' and a Service Principal Name has been registered for the SQL Server to allow Kerberos authentication.

We have configured the connection string to use SQL Authentication (user name and password). We have tried setting trusted_connection=false, but the connection still attempts to use Kerberos authentication.

The (redacted) connection string is:

"server=ourfullyqualifiedserver.domain,1433;database=our-database;user=sql-user;password=sql-password;"

I would expect to be able to connect to SQL Server from the container using SQL Authentication, but it is still attempting to use Kerberos. Why, and how do we make the connection use SQL Server Authentication?

Answer 1

You may have to add "Trusted_Connection=false;" to your connection string. And also, use the Server IP with the Port that you exposed to the server.

Answer 2

It turns out that the connection string in the base appsettings.json configuration file was not being overwritten by the environment-specific settings file (appsettings.Development.json). Our DevOps group set the environment variable for the container and it correctly connected using the SQL Server credentials.