You will need to create a file named “.qmail-XXXX” where “XXXX” depends on the email alias you wish to create. In this example, I’m using “firstname.lastname@example.org”, therefore the file name will become “.qmail-bounce”. If you were to make your alias “email@example.com” the name of the file would’ve been “.qmail-mybouncealias”. Create this file in your home directory (not your public html folder but one level up from that) for the specified domain. With the file created, put the following line of code into it.
Ensure that the path is the actual, correct path to your CGI-bin directory. With the file saved, CHMOD it to 0755 in order to make it executable.