The name of file to log authentication attempts to. Attempts
                  where the user is not found, are not logged. The default is no logging.
                  The file name can include 
Section 3.3. Special formatters, which means that
                  using the %C, %c and %R specifiers, you can maintain separate password log
                  files for each Realm or Client or a combination.
 
               Each login attempt
                  that generates a password check will be logged to the file, one attempt
                  per line. For more information about file format, see 
Section 9.6. Password log file.
 
               # Help desk want to see all password attempts
PasswordLogFileName %L/password.log
               If the file name starts with
                  a vertical bar character ('|') then the rest of the filename is assumed to
                  be a program to which the output is to be piped. Otherwise the output will
                  be appended to the named file:
               # Pipe to my-log-prog
PasswordLogFileName |/usr/local/bin/my-log-prog