When piping email to a script, does the script need to set a return value to indicate that the email has been accepted?

Question

I've set up a Perl script to process incoming emails through qmail. However, I find that email messages are hitting the script over and over again, every few minutes for several hours.

Am I supposed to set a return value in the script or do something else to indicate to the sender that the email has been received successfully?

Answer 1

Depends on the MTA but yes, generally any nonzero exit code signals an error. Qmail uses different codes than Sendmail and compatibles, in the 100-something range.