Connection to SQL Server 2000 fails with unhelpful message; missing supported versions documentation

[LaXiS96]

Hello,

I have lots of legacy SQL Server 2000 instances to connect to, but connections fail with an unhelpful message (NuGet v5.0.1):

System.InvalidOperationException: Internal connection fatal error.
   at Microsoft.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at Microsoft.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
   at Microsoft.Data.SqlClient.SqlInternalConnectionTds.CompleteLogin(Boolean enlistOK)
   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.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
   at Microsoft.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at Microsoft.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at Microsoft.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at Microsoft.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at Microsoft.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
   at Microsoft.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at Microsoft.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at Microsoft.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry, SqlConnectionOverrides overrides)
   at Microsoft.Data.SqlClient.SqlConnection.Open(SqlConnectionOverrides overrides)
   at Microsoft.Data.SqlClient.SqlConnection.Open()
   at Program.<Main>$(String[] args) in C:\Users\...\Source\Repos\ConsoleApp1\ConsoleApp1\Program.cs:line 10

As far as I understand, the problem is related to the TDS protocol version, which for SQL Server 2000 is 7.1. I also tried connecting to a 2008 R2 instance (TDS 7.3.B) and that works.

It took me a while to get to the conclusion that there is no problem with the servers I am connecting to, and the problem is in SqlClient not supporting that old of a version.
There doesn't seem to be any documentation where it is clearly stated which SQL Server/TDS versions are supported and which aren't, can it be added?

Thanks

[JRahnama]

@LaXiS96 SQL Server 2000 is out of support. Currently TDS 7.4 being used for supported versions which start from 2012 up to 2019. TDS 8 is added for SQL Server 2022 as well. Basically, the driver supports the supported versions of SQL Server by Microsoft.

[ErikEJ]

see https://learn.microsoft.com/en-us/sql/connect/ado-net/sqlclient-driver-support-lifecycle?view=sql-server-ver16#sql-version-compatibility-with-microsoftdatasqlclient

[MaceWindu]

@LaXiS96 SQL Server 2000 (and older versions) support was dropped in .net core version of driver, but still here for .net framework builds

[JRahnama]

Closing this due to inactivity and not supported version of Sql Server version.