Symptoms

The following problems may have occurred while connecting to an older version of Microsoft SQL Server:

 [bob@localhost ~]$ isql -v MSSQL10.0_VMDBSRV002_ETEST sa Ispirer_1999
 [08001][unixODBC][Microsoft][ODBC Driver 17 for SQL Server]TCP Provider: Error code 0x2746
 [08001][unixODBC][Microsoft][ODBC Driver 17 for SQL Server]Client unable to establish connection
 [ISQL]ERROR: Could not SQLConnect
  
 [bob@localhost ~]$ isql -v MSSQL12.0_VMDBSRV021_ETEST sa Ispirer_1999
 [08001][unixODBC][Microsoft][ODBC Driver 17 for SQL Server]SSL Provider: [error:1425F102:SSL routines:ssl_choose_client_version:unsupported protocol]
 [08001][unixODBC][Microsoft][ODBC Driver 17 for SQL Server]Client unable to establish connection
 [ISQL]ERROR: Could not SQLConnect

Cause

Most likely, this is a problem with the protocol/version of openssl vs sql-server. An SSL provider error usually indicates a problem with the SSL/TLS protocol version. The SQL server you are trying to connect to may not support the version of SSL/TLS that your client system is using.

Solution

The recommended solution is to install updates for your SQL Server.

Another solution is to enable legacy encryption, but TLS 1.0 is deprecated for some reason. It will also be completely removed in the future.

 # Enable TLS v1.0. This is definitely not recommended though.
 sudo update-crypto-policies --set LEGACY
 # Restart is required.

You can find more detailed information in the How to enable TLSV1.0 in rhel 8 for openssl article.

If you have any questions or encounter any difficulties, please contact us at support@ispirer.com