Monday, August 2, 2010

Handling Bounces yourself

IndiMail allows a mechanism by which you can use your own script/program to handle bounces. All bounces in IndiMail is generated by qmail-send. qmail-send generates a bounce when qmail-lspawn or qmail-rspawn reports a permanent failed delivery. A bounce is generated by qmail-send by injecting a new mail in the queue using qmail-queue. This bounce generation by qmail-send can be modified in three ways

1. Using environment variable BOUNCEPROCESSOR

When you define the environment variable BOUNCEPROCESSOR as a valid path to a program or script, the program gets called whenever a delivery fails permanently. The program runs with the uid qmails and is passed the following five arguments

bounce_file bounce_report bounce_sender original_recipient bounce_recipient

To set BOUNCEPROCESSOR, you would do the following

# echo "path_of_your_bounce_processor" > /service/qmail-send.25/variables/BOUNCEPROCESSOR

There are few email marketing companies who are using BOUNCEPROCESSOR to insert the status of all bounces in MySQL table for their email marketing campaigns.

2 Using environment variable BOUNCERULES or control files bounce.envrules.

Using envrules, you can set specific environment variables only for bounced recipients. The format of  this  file  is  of  the  form

pat:envar1=val,envar2=val,...]

where pat is a regular expression which matches a bounce recipient.  envar1, envar2 are list of environment variables to be set. If var is omitted, the environment variable is unset.

e.g.

support@indimail.org:CONTROLDIR=control2,QMAILQUEUE=/var/indimail/bin/qmail-nullqueue

causes all bounces generated for the sender support@indimail.org to be discarded.

3. Using BOUNCEQUEUE environment variable to queue bounces


qmail-send  uses  qmail-queue to queue bounces and aliases/forwards. This can be changed by using QMAILQUEUE environment variable. If a different queue program is desired for bounces, it can be set by using BOUNCEQUEUE environment variable.

e.g

# echo /var/indimail/bin/qmail-nullqueue > /service/qmail-send.25/variables/BOUNCEQUEUE

disables bounces system-wide. Though disabling bounces may not be the right thing to do but in some situations where bounces are not at all needed, disabling bounces will surely result in performance improvements of your system, especially so if your system does mass-mailing.

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