Dovecot LDA with Postfix
========================

This page contains only information specific to using LDA with Postfix, see
<LDA.txt> for more information about using the LDA itself.

System users
------------

If you wish you use 'deliver' for all system users on a single domain mail host
you can do it by editing 'mailbox_command' parameter in

'/etc/postfix/main.cf' (postconf(5) [http://www.postfix.org/postconf.5.html]):

---%<-------------------------------------------------------------------------
mailbox_command = /usr/local/libexec/dovecot/deliver
#  or
mailbox_command = /usr/libexec/dovecot/deliver
#  or
mailbox_command = /usr/lib/dovecot/deliver
#  or wherever it was installed in your system.
---%<-------------------------------------------------------------------------

Then run 'postfix reload' and that is it (be sure that /var/mail or wherever
you deliver mail is writable by the deliver process which does not run as
root).

Note: Postfix's mailbox_size_limit setting applies to all files that are
written via local(8), which interfaces Dovecot deliver.  So if you have
mailbox_size_limit = 51200000 (Postfix default setting), deliver won't be able
to write to existing mbox files that will exceed 51200000 bytes after writing
the new message into the file.  You will _not_ see a Postfix error in your logs
if this occurs, even though the parameter causing the error condition is a
Postfix parameter.  You will see a Dovecot entry similar to this:

---%<-------------------------------------------------------------------------
Jan 1 00:00:00 hostname dovecot: deliver(user): write() failed with mbox file
/home/user/mail/foo: File too large
---%<-------------------------------------------------------------------------

If you use Dovecot sieve to sort messages into IMAP folders that are mbox
files, and an mbox file reaches the above limit, you will also see related
error messages such as these below directly following the error message above. 
In this example the INBOX file is /var/mail/user and is relatively empty due to
previous sieve sorting.  Sieve falls back and delivers the message to the INBOX
folder when it finds the sort destination folder exceeds the Postfix
mailbox_size_limit:

---%<-------------------------------------------------------------------------
Jan 1 00:00:00 hostname dovecot: deliver(user): write() failed with mbox file
/home/user/mail/foo: File too large
Jan 1 00:00:00 hostname dovecot: deliver(user): sieve:
msgid=<xxxx@xxxx.xxxx.xxx>: failed to store into mailbox 'foo': Internal error
occurred. Refer to server log for more information. [2010-01-01 00:00:00]
Jan 1 00:00:00 hostname dovecot: deliver(user): sieve:
msgid=<xxxx@xxxx.xxxx.xxx>: stored mail into mailbox 'INBOX'
Jan 1 00:00:00 hostname dovecot: deliver(user): sieve: execution of script
/home/user/.dovecot.sieve failed, but implicit keep was successful
---%<-------------------------------------------------------------------------

Some detailed config files and examples at
http://heinous.org/wiki/Virtual_Domains%2C_Postfix%2C_Dovecot_LDA%2C_and_LDAP
[http://heinous.org/wiki/Virtual_Domains,_Postfix,_Dovecot_LDA,_and_LDAP]

Virtual users
-------------

Dovecot LDA is very easy to use on large scale installations with Postfix
virtual domains support, just add a 'dovecot' service in
'/etc/postfix/master.cf' (master(5) [http://www.postfix.org/master.5.html]):

---%<-------------------------------------------------------------------------
dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/usr/local/libexec/dovecot/deliver -f
${sender} -d ${recipient}
---%<-------------------------------------------------------------------------

An example using address extensions (ie user+extension@domain.com (don't forget
to define the proper recipient_delimiter in Postfix's main.cf)) to deliver to
the folder 'extension' in your maildir (If you wish to preserve the case of
${extension}, remove the 'hu'flags [http://www.postfix.org/pipe.8.html], and be
sure to utilize <Modifiers> [Variables.txt] in your dovecot.conf for mail
locations and other configuration parameters that are expecting lower case):

---%<-------------------------------------------------------------------------
dovecot unix    -       n       n       -       -      pipe
  flags=DRhu user=vmail:vmail argv=/usr/local/libexec/dovecot/deliver -f
${sender} -d ${user}@${nexthop} -n -m ${extension}

# or with v1.1.2+ if you have a INBOX/ namespace prefix:
dovecot unix    -       n       n       -       -      pipe
  flags=DRhu user=vmail:vmail argv=/usr/local/libexec/dovecot/deliver -f
${sender} -d ${user}@${nexthop} -n -m INBOX/${extension}
---%<-------------------------------------------------------------------------

This example ignores address extensions (ie user+extension@domain.com delivers
just like user@domain.com):

---%<-------------------------------------------------------------------------
dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/usr/lib/dovecot/deliver -f ${sender} -d
${user}@${nexthop}
---%<-------------------------------------------------------------------------

Replace 'vmail' above with your virtual mail user account.

Then set 'virtual_transport' to 'dovecot' in '/etc/postfix/main.cf':

---%<-------------------------------------------------------------------------
dovecot_destination_recipient_limit = 1
virtual_mailbox_domains = your.domain.here
virtual_transport = dovecot
---%<-------------------------------------------------------------------------

And remember to run

---%<-------------------------------------------------------------------------
postfix reload
---%<-------------------------------------------------------------------------

Virtual users with multiple uids/gids
-------------------------------------

If you need multiple uids/gids you'll need to set deliver setuid root or invoke
it through sudo. See the <LDA.txt> main page how to do this securely.

Postfix mail_debug caveat
-------------------------

This is a problem with Dovecot versions older than v1.0.1:

Be sure that the 'mail_debug' setting is commented out in 'dovecot.conf',
because otherwise the postfix sendmail replacement will be started in the
debugger using debugger_command [http://www.postfix.org/DEBUG_README.html] and
delayed for five seconds. It is not enough to set 'mail_debug' to 'no', because
postfix's sendmail command checks for the existence of the MAIL_DEBUG
environment variable, which is created by the dovecot lda as soon as a
'mail_debug' setting is present.

Postfix with a NFS mail store
-----------------------------

If you are experiencing problems with deliver processes hanging when delivering
to a NFS mail store, it's likely that the deliver process is hanging while
waiting for free locks.  The occurrence of this can be greatly reduced, if not
eradicated, by forcing Postfix to only deliver to the same recipient one at a
time.

---%<-------------------------------------------------------------------------
dovecot_destination_concurrency_limit = 1
---%<-------------------------------------------------------------------------

(This file was created from the wiki on 2010-06-01 04:42)
