[Dovecot] From Sendmail to Dovecot mdbox, what is missing.

[Ben Morrow]

At  5PM -0600 on 31/12/12 you (Torpey List) wrote:
> Sendmail 8.14.4
> dovecot 2.0.9
> 
> I have sendmail working and it is sending mail to /var/mail/%u.
> I have dovecot working in that I can move emails into IMAP folders and
> I can send email through IMAP.  I have set up dovecot to use mdbox
> based on the following:
> mail_location = mdbox:~/mail
> 
> However, I seem to be lacking a key piece of information.  
> Sendmail is sending the mail to /var/mail/%u as a mbox (single file
> for all emails) format.
> Dovecot wants to read the mail in mdbox (Multiple messages per file,
> but unlike mbox multiple files per mailbox.)  So the two programs are
> not working together.
> 
> So, I cannot get dovecot to read new emails at /var/mail/%u.
> So I tried changing to the following:
> mail_location = mdbox:~/mail:INBOX=/var/mail/%u
> However, dovecot complains that it is NOT a directory.  That is
> because sendmail is sending as mbox format.
> 
> I have tried two lines of “mail_location” but that did not work.
> example
>         mail_location = mdbox:~/mail               ----> for dovecot
>         mail_location = mbox:INBOX=/var/mail/%u    -----> for sendmail

No, that doesn't work: in fact, the second line will completely override
the first. If you run 'doveconf -n' or 'doveconf mail_location' you will
see that the first line doesn't have any effect.

If you want to keep INBOX delivery to mboxes in /var/mail, you can do
this using two namespaces. One points to mdbox:~/mail, and holds the
users' ordinary IMAP folders in mdbox format, and the other has
INBOX=/var/mail/%u and just holds the INBOX. There is an example in
http://wiki2.dovecot.org/Namespaces of doing this with Maildir and mbox;
adjusting it for mdbox shouldn't be hard. 

You will find you need a directory for each user to hold the other
folders in the INBOX namespace, since Dovecot doesn't know there won't
ever be any. This directory is also used to store Dovecot's index files
for that namespace, and it should *not* be the same as the mdbox
directory. According to http://wiki2.dovecot.org/MailLocation/mbox , you
can skip this if you use

    location = mbox:/var/empty:INBOX=/var/mail/%u:INDEX=MEMORY

(assuming /var/empty is a readonly root-owned empty directory), but
since this tells Dovecot not to store index files on disk it may make
INBOX access less efficient. If you use a real directory rather than
/var/empty you may want to consider enabling the acl plugin and setting
up a global ACL which prevents users from creating additional folders in
the INBOX namespace.

It's probably also a good idea to set mail_location = mdbox:~/mail and
omit the location parameter from the mdbox namespace, since IIRC
otherwise commands like 'doveadm purge' won't work correctly.

> I have tried LMTP and dovecot-lda.

If you want to deliver mail into the mdbox INBOX, and forget about
/var/mail altogether, you will need to get one of these two working
since Sendmail doesn't understand mdbox. This is probably the best
option in the long run, unless you have other software which relies on
mail being in /var/mail. If you pick this option you need to remove all
references to /var/mail from dovecot.conf; with the two lines you had
above Dovecot will simply carry on delivering into /var/mail just as
Sendmail had been.

> LMTP – I could not see any difference with this added or not.

If you had configured Dovecot to deliver into /var/mail, that's hardly
surprising. Otherwise, are you sure you were delivering mail to the LMTP
server? If you were you should have seen entries in Dovecot's log file,
and the delivered mail should have ended up with a Received header from
the LMTP server.

> Dovecot-lda – I have had issues getting it configured.

What issues? If you were trying to get the LDA to deliver to /var/mail,
it's possible you were running into permissions problems. The best
solution is to deliver into the mdbox instead, or just leave Sendmail to
deliver to /var/mail.

> Sendmail changes
> FEATURE(`local_procmail',
> `/usr/libexec/dovecot/dovecot-lda',`/usr/libexec/dovecot/dovecot-lda
> -d $u')
> MODIFY_MAILER_FLAGS(`LOCAL', `-f')
> MAILER(procmail)dnl

I know nothing at all about Sendmail configuration, but going by the
Dovecot wiki that looks correct. Are you sure mail for the appropriate
users was actually getting routed through that mailer? What did you see
in the logs (you need to check both Dovecot's and Sendmail's logs,
wherever they may be).

Ben