Phillip T. George schrieb:
Here's a snippet from the procmail log file: procmail: Assigning "LASTFOLDER=/home/domain.com/homes/user/Maildir/new/1176426436.9170_1.east.domain.com"
procmail: Notified comsat: "user.domain.com@0:/home/domain.com/homes/user/Maildir/new/1176426436.9170_1.east.domain.com"
I do not see any errors near the time the duplicate messages occurred.
In /etc/postfix/main.cf : home_mailbox = Maildir/ mailbox_command = /usr/bin/procmail -a "$EXTENSION"
mailbox_command overrides home_mailbox - if you commented this one out, you'd get procmail out of the loop, but I'm not sure if you can actually do that, as it bypasses filtering and procmailrc of all other users where it's apparently working properly.
Personally, I'd say if you don't trust procmail, try maildrop - in particular, it omits the nastiest of all promail misfeatures, namely "fallthrough" behavior to implicit (thus, hidden!) default mailboxes. http://www.courier-mta.org/
Configuring procmail properly is a subject in itself. I know some typical pitfalls, that the typical procmailrc samples do not address, but the procmail maintainers used to withdraw to their retreat of claiming "well, you have the liberty of handling errors", but I haven't bought that reason and I'm not going to. Procmail's defaults are just utterly inadequate.