How to use recipient_delimiter with spamd and dovecot?

Question

I want to use recipient_delimiter to allow addresses like user+anything@domain in a setup involving spamd and dovecot.

I had a setup like this in the past with just using postfix, but with my setup using spamd and dovecot deliver it does not work as it seems that spamd/dovecot are searching for the mailbox user+anything@domain instead of user@domain.

The corresponding line in my master.cf is:

spamc     unix  -       n       n       -       -       pipe
    flags=DRhu user=vmail:vmail argv=/usr/bin/spamc -e /usr/lib/dovecot/deliver -f ${sender} -d ${recipient}

I read that the way to get it working with maildrop is

maildrop  unix  -       n       n       -       -       pipe
  flags=DRhu user=Debian-exim argv=/usr/bin/maildrop -d ${user}@${nexthop}
  ${extension} ${recipient} ${user} ${nexthop}

But I do not get it working with spamc and deliver. Which of the variables is the correct one and are the programs parsing the To header on their own?

Answer 1

Try to use dovecot-lda like this:

dovecot-lda -f ${sender} -d ${user}@${nexthop} -m ${extension}

Answer 2

The answer here was to use ${user}@${domain} as ${user} does not automatically follow the username scheme (which is in my case user@domain) configured for postfix, but always contains the user part of a address in the form user+foo@domain.