The connection string should be:
Provider=SQLNCLI10;Password=Rave123;Persist Security Info=True;User ID=Usr123;Initial Catalog=sqldb12;Data Source=<IP address>
Or if it is a named instance:
Provider=SQLNCLI10;Password=Rave123;Persist Security Info=True;User ID=Usr123;Initial Catalog=sqldb12;Data Source=<IP address>\<instance name>;
So if it is SQLExpress as a named instance:
Provider=SQLNCLI10;Password=Rave123;Persist Security Info=True;User ID=Usr123;Initial Catalog=sqldb12;Data Source=<IP address>\SQLExpress