Dovecot LDA with Postfix
This page contains only information specific to using LDA with Postfix, see LDA for more information about using the LDA itself.
System users
If you wish to 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)):
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: to make vacation auto-reply of the Sieve plugin work, a valid recipient needs to be specified to deliver. This can be done by adding -a "${RECIPIENT}" to the command (Dovecot 1.1+).
Note: to make vacation use the correct domain part for the sender address for a user with multiple domain addresses you might need to use the -a "${ORIGINAL_RECIPIENT}" command line option (Dovecot 1.1+).
Note: you can provide simple header-rewriting (which can then be processed via sieve) by invoking spamc, if the spamd daemon is running:
mailbox_command = /usr/bin/spamc -e /usr/lib/dovecot/deliver
(modify as appropriate for your path)
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
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)):
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, and be sure to utilize Modifiers 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}
# As above, but if you have migrated from Courier the namespace will probably be INBOX.
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 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 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
null_sender Problem
If you have problems with your bounces because they contain Return-Path: <MAILER-DAEMON>, add null_sender= to master.cf of Postfix.
Example:
dovecot unix - n n - - pipe
flags=DRhu user=vmail:vmail null_sender= argv=/usr/lib/dovecot/deliver -f ${sender} -d ${user}@${nexthop}
case sensitive mailaddresses
You should use flags=DR (without hu) if you have case sensitive directories for storing mails. Otherwise dovecot delivers all mails to the wrong directory.