Connecting to DAC from ADS on Mac > Docker fails with admin:localhost

[jdanton]

Describe the bug

When trying to connect to the DAC on a Docker container on MacOS, Azure Data Studio returns the following error when using "admin:localhost" as the server name. Using "admin:127.0.0.1" is successful. Connecting using sqlcmd -Usa -I -S admin:localhost also works sucessfully.

Microsoft.Data.SqlClient.SqlException (0x80131904): 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.Net.Internals.SocketExceptionFactory+ExtendedSocketException (00000005, 0xFFFDFFFF): nodename nor servname provided, or not known
at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, ValueStopwatch stopwatch)
at System.Net.Dns.GetHostAddresses(String hostNameOrAddress, AddressFamily family)
at Microsoft.Data.SqlClient.SNI.SNITCPHandle.Connect(String serverName, Int32 port, TimeSpan timeout, Boolean isInfiniteTimeout, SqlConnectionIPAddressPreference ipPreference, String cachedFQDN, SQLDNSInfo& pendingDNSInfo)
at Microsoft.Data.SqlClient.SNI.SNITCPHandle..ctor(String serverName, Int32 port, Int64 timerExpire, Boolean parallel, SqlConnectionIPAddressPreference ipPreference, String cachedFQDN, SQLDNSInfo& pendingDNSInfo)
at Microsoft.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action1 wrapCloseInAction) at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) at Microsoft.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover, SqlAuthenticationMethod authType) at Microsoft.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover) at Microsoft.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout) at Microsoft.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance) at Microsoft.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling, String accessToken, DbConnectionPool pool) at Microsoft.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) at Microsoft.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup, DbConnectionOptions userOptions) at Microsoft.Data.ProviderBase.DbConnectionFactory.<>c__DisplayClass48_0.<CreateReplaceConnectionContinuation>b__0(Task1 _)
at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
at System.Threading.Tasks.Task.<>c.<.cctor>b__272_0(Object obj)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
--- End of stack trace from previous location ---
at Microsoft.SqlTools.ServiceLayer.Connection.ReliableConnection.ReliableSqlConnection.<>c__DisplayClass30_0.<b__0>d.MoveNext() in D:\a_work\1\s\src\Microsoft.SqlTools.ManagedBatchParser\ReliableConnection\ReliableSqlConnection.cs:line 312
--- End of stack trace from previous location ---
at Microsoft.SqlTools.ServiceLayer.Connection.ConnectionService.TryOpenConnection(ConnectionInfo connectionInfo, ConnectParams connectionParams) in D:\a_work\1\s\src\Microsoft.SqlTools.ServiceLayer\Connection\ConnectionService.cs:line 642
ClientConnectionId:00000000-0000-0000-0000-000000000000

Exception message:
Stack trace:

To reproduce

docker run -e 'ACCEPT_EULA=Y' -e 'SA_PASSWORD=P$YourStrongPassword' -e'MSSQL_PID=Developer' -p 1433:1433 -p 1434:1434 -v /Users/joey/mssql:/mssql -d mcr.microsoft.com/mssql/server:2022-latest

exec sp_configure 'remote admin connections', 1
GO
RECONFIGURE
GO

Then issue the admin connection via ADS.

Expected behavior

The connection should work.

Further technical details

Microsoft.Data.SqlClient version: (found on the nuget or Microsoft.Data.SqlClient.dll)

Version: 1.39.1
Commit: 7553f799e175f471b7590302dd65c997b838b29b
Date: 2022-08-30T01:12:48.559Z
VS Code: 1.62.0
Electron: 13.6.6
Chrome: 91.0.4472.164
Node.js: 14.16.0
V8: 9.1.269.39-electron.0
OS: Darwin x64 21.6.0

SQL Server version: SQL Server 2022
Operating system: MacOS 12.6, Docker Desktop 4.10.1
Additional context
Add any other context about the problem here.

[lcheunglci]

Thanks for reporting the issue. We will look into it.