I’ve previously written about both Virtual Mail users, and about enabling vacation messages for postfix. The next step was to get vacation working with virtual users.
My first thought was to try and make the sendmail ‘vacation’ program work with virtual users, but after digging into that a bit, it looked like more trouble than it was worth. I remembered that PostfixAdmin had some kind of support for this, so I decided to check it out, which proved a much more promising solution.
PostfixAdmin ships with a perl-based script that can be piped an email message and then will send an auto-reply to the sender. The script is able to grab a customized subject and message body from a MySQL database and then reply to senders as appropriate. It also keeps track of who it has auto-replied to so that each sender only gets one auto-reply in a given length of time.
The instructions for implementing it can be found at http://postfixadmin.svn.sourceforge.net/viewvc/postfixadmin/trunk/VIRTUAL_VACATION/INSTALL.TXT?view=markup. I found the documentation to be fairly straightforward.
Essentially, when a user enables the auto-reply, it adds an email address to the aliases table that points to user#domain@autoreply.yourdomain.com. You then configure postfix to send everything to the ‘autoreply.yourdomain.com’ domain to the vacation script, which then can read the original recipient’s address and respond as desired.
I now have this working on our hosted mail solution, so that RoundSphere mail customers now have auto-reply functionality. In addition, I made an addition to the webmail application (RoundCube) so that users can modify their vacation message themselves instead of having to have a mail administrator do it through postfixadmin.