exim dovecot procmail mdbox

When using an mdbox or maildir mailbox, you need to use the dovecot-lda to deliver the message and not allow procmail to do this directly. I had a few issues getting this to work properly, here are the details of getting it going.

The first issue is that my procmail transport in exim needed to set user to the local_part and do initgroups to get the uid and gid of the localuser, then run procmail as that user/group. Here is that transport:


procmail_pipe:
driver = pipe
command = /usr/bin/procmail -d $local_part
…