DB2 Version 9.7 for Linux, UNIX, and Windows

FileDSN CLI/ODBC configuration keyword

Specifies a DSN file from which a connection string will be built for the data source.

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:
FileDSN = file name