In the TSO environment, the location specified by the FTPRXTRC DD statement is used as the FTP client API for REXX trace output location. Use the TSO ALLOCATE command to associate FTPRXTRC with these outputs. Following is an example:

 ALLOC FILE(FTPRXTRC) DA(FTP.TRACE.OUT) NEW LRECL(80) RECFM(F B) TRACK SPACE(10 10)

See z/OS TSO/E Command Reference for more details about using the ALLOCATE command.