Connecting to SqlServer from .Net Core on Ubuntu/Visual Studio Code

Question

I've got a console application that connects to a SQL Server DB (hosted on a dedicated win machine within the same network), written in .Net core (using Visual Studio Code) and it's working perfectly fine on Windows.

The very same code base running on Visual Studio Code on Ubuntu can't connect to the SQL Server instance saying it cannot find the server.

I can ping the SQL Server IP and get response from it.

Also I can connect to the SQLServer instance using telnet on the 1433 port.

Also, I have pulled the System.Data.Common and System.Data.SqlClient from nuget as recommended and set MultipleActiveResultSets=False in the connection string as recommended as well.

Just for completeness, this is the code that tries to connect:

var connection = new SqlConnection(myConnectionString);
connection.Open();

And this is the stacktrace:

Unhandled Exception: System.Data.SqlClient.SqlException: 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. (provider: TCP Provider, error: 35 - An internal exception was caught) ---> System.AggregateException: One or more errors occurred. (No such device or address) ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException: No such device or address
   at System.Net.Dns.HostResolutionEndHelper(IAsyncResult asyncResult)
   at System.Net.Dns.EndGetHostAddresses(IAsyncResult asyncResult)
   at System.Net.Dns.<>c.<GetHostAddressesAsync>b__14_1(IAsyncResult asyncResult)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Data.SqlClient.SNI.SNITCPHandle.<ConnectAsync>d__22.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait(TimeSpan timeout)
   at System.Data.SqlClient.SNI.SNITCPHandle..ctor(String serverName, Int32 port, Int64 timerExpire, Object callbackObject, Boolean parallel)
   --- End of inner exception stack trace ---
   at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
   at System.Data.SqlClient.SqlConnection.Open()

Any ideas?

Thanks

What does your connection string look like? Are you using SQL Authentication? If your connection string is using windows authentication instead of sql authentication, you'll likely have issues. — Robert Paulsen
– Robert Paulsen, Commented Jul 29, 2016 at 13:21
I am using SQL authentication. "SERVERIP\\MSSQLSERVER,1433;Database=DBName;User=UIsername;Password=password;MultipleActiveResultSets=False" — Alessandro Di Lello
– Alessandro Di Lello, Commented Jul 29, 2016 at 13:54

Alessandro Di Lello · Accepted Answer · 2016-07-29 15:37:10Z

5

I found the problem and it was already raised as an issue in the coreclr repo. The problem is the SQLServer instance version I'm connecting to. It's 2008r2 SP1 and the .net core sql client just can't connect to it. Upgrade to SP3 fixes it.

More details here

answered Jul 29, 2016 at 15:37

Alessandro Di Lello

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Comments

It's a trap · Accepted Answer · 2016-07-29 14:47:54Z

0

Obviously, as the SQL server was present on your windows machine and it is not there on your Ubuntu machine. And it can't be installed on Ubuntu machine. You have to host it on a db server even for testing purposes, and point your connection string to that.

Edit
Try to make sure that your db server's firewall is not blocking access. Even if you have dual boot in same pc, they are still 2 different machines for computers.

edited Jul 29, 2016 at 14:47

answered Jul 29, 2016 at 11:56

It's a trap

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12 Comments

Alessandro Di Lello Over a year ago

Sorry I should have specified that. I am already connecting to a DB server hosted remotely (still in the LAN and on a dedicated win machine). As I mentioned in the question, I can ping the SQL Server machine and I do get a response from it.

It's a trap Over a year ago

Then check your db server firewall rules.

Alessandro Di Lello Over a year ago

Why should that change when connecting from Ubuntu? I can connect from my machine when I run my app on Windows. (I do have dual boot on my machine)

Krishnandu Sarkar Over a year ago

Try to telnet / ssh into port 1433. That's the port used by SQL Server and see if you can successfully connect.

Krishnandu Sarkar Over a year ago

Well if your DB Server is different and you are trying to run the code in Dual Boot Windows and Ubuntu PC, and you are able to connect from Windows but not from Ubuntu, that might mean, Ubuntu is blocking the connection to port 1433 or so. As I said above you may try to Telnet / SSH into 1433 and check if it works

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