batch file catch error

my package using Execute process task to run a batch file to FTP upload file.

batch file as below: 

LOG \\xxx\Script\log.txt
TRACE \\xxx\Script\trace.txt

CONNECT xxxTest

LCD \\xxx\Test
CD /dev/Test

MPUT *.xls
CLOSE

so my questions is: how can I catch error if this code "CONNECT xxxTest" fail ?

I mean, how can I make Execute process task fail if the connection fail ?

Thank you.