DB2 Version 9.7 for Linux, UNIX, and Windows

DSN CLI/ODBC configuration keyword

Sets the name of a data source as returned by SQLDataSources or the data sources dialog box of SQLDriverConnect.

db2cli.ini keyword syntax:
You can not set this keyword in the db2cli.ini file.
You can specify the value of this keyword in the connection string in SQLDriverConnect like this:
DSN = database name