[Dovecot] dovecot lda and postfix

[Patrick Domack]

There isn't enough info for me to say what is going on, but it is a  
postfix problem. I am using 100% postfix virtual users, and it checks  
the virtual tables before passing it to virtual_transport (dovecot lda  
in my case).

The issue is probably the restrictions lines, like  
smtp_recipient_restrictions, not having a line to reject unknown  
recipients. But could be any number of issues, that is just the  
simplest.

Quoting Mauricio Tavares <raubvogel at gmail.com>:

>       I do not know if this is a help request to solve a problem but
> to understand what is going on. I am going to start with the problem
> description as I see it and we will go from there.
>
> I have postfix setup to use dovecot for tls/sasl in addition to its
> normal imap/pop3 functions. Postfix is also setup to do virtual
> domains, getting its information from the files valias, vmaps, and
> vhosts which are all located in its /etc/postfix directory:
>
> # Virtual domain stuff
> virtual_mailbox_domains = /etc/postfix/vhosts.txt
> virtual_mailbox_base = /var/spool/vmail
> virtual_mailbox_maps = hash:/etc/postfix/vmaps.txt
> # 1500:1500 is user virtual
> virtual_uid_maps = static:1500
> virtual_gid_maps = static:1500
> virtual_alias_maps = hash:/etc/postfix/valias.txt
>
> Dovecot uses its own unix passwd-like files to do authentication. In
> fact, as you can see, I broke them apart so I can make the actual
> password file readable only by root:
>
> mail_location = maildir:~/
>
> auth default {
>   passdb passwd-file {
>      args = /etc/dovecot/passwd
>   }
>   userdb passwd-file {
>      args = /etc/dovecot/users
>   }
> }
>
> I know the norm is to use a database or at least ldap, but I had my
> reasons. Mailscanner is also installed. So, the whay things have been
> working so far was, postfix receives an email and checks if it is
> recipient exists here. If so, it would pass it to mailscanner and then
> get it back, when it would then drop it at the recipient's mailbox in
> /var/spool/vmail/domain.com/user. A user would then connect to dovecot
> to retrieve the email. And when an email was to be sent, postfix would
> use dovecot to do the user authentication. So far so good.
>
> Now I want to add dovecot lda so I can run the cmu sieve plugin (this
> is dovecot 1.0.1) primarily to move emails mailscanner (and
> spamassassin) thinks that are spam to each virtual  user's  Spam
> maildir directory.
>
> So, reading http://wiki.dovecot.org/LDA/Sieve/CMU, I add the following
> entries to dovecot.conf:
>
> protocol lda {
>   mail_plugin_dir = /usr/lib/dovecot/modules/lda
>
>   sendmail_path = /usr/lib/sendmail
>
>   auth_socket_path = /var/run/dovecot/auth-master
>   mail_plugins = cmusieve
>   global_script_path = /etc/dovecot/scripts/dovecot.sieve
>
>   mail_debug = yes
>   log_path = /var/log/dovecot-lda
>   info_log_path = /var/log/dovecot-lda
>
> }
>
> # I am being rather lazy in my sieve config entry. I did make sure the file
> # is owned by virtual:virtual
> plugin {
>   sieve = /etc/dovecot/scripts/dovecot.sieve
> }
>
>   socket listen {
>     master {
>       path = /var/run/dovecot/auth-master
>       mode = 0600
>       user = virtual # User running Dovecot LDA's deliver
>     }
>     # Postfix is using dovecot for SMTP AUTH (SASL)
>     client {
>        path = /var/spool/postfix/private/auth
>        mode = 0660
>        user = postfix
>        group = postfix
>     }
>   }
>
> Then, based on http://wiki.dovecot.org/LDA/Postfix, I edit postfix's  
>  master.cf:
>
> dovecot   unix  -       n       n       -       -       pipe
>   flags=DRhu user=virtual:virtual argv=/usr/lib/dovecot/deliver -f
> ${sender} -d ${user}@${nexthop}
>
> and main.cf:
> dovecot_destination_recipient_limit = 1
> virtual_transport = dovecot
> # mailbox_virtual_domains was already defined as shown above
>
> The dovecot.sieve file looks like this:
>
> require ["fileinto", "reject"];
>
> # Spam stuff
> if header :contains "X-Spam-Level" "********************" {
>         discard;
>         stop;
> }
> elsif header :contains "X-Spam-Status" "Yes" {
>         fileinto "Spam";
>         stop;
> }
>
> So, I restart it and try to send a message to my account, say
> raub at domain.com, in this machine. It bounces back saying the user does
> not exist. I check th elog files and they seem to agree:
>
> dovecot: 2009-06-30 16:31:44 Info: auth(default):
> passwd-file(raub at domain.com): lookup: user=raub at domain.com
> file=/etc/dovecot/users
> dovecot: 2009-06-30 16:31:44 Info: auth(default):
> passwd-file(raub at domain.com): unknown user
>
> Now this is where I am trying to understand what is going on. It seems
> to me that postfix *or* dovecot went to  /etc/dovecot/users looking
> for raub at domain.com. Not finding it there (I had it defined there as
> raub simply; I have mail_location = maildir:~/ in dovecot.conf, so the
> username in this file does not need to be related to the user's email
> address), it decided user does not exist and bounced back.
>
> My testing indicated that happened after postfix passed the email to
> dovecot lda (I guess that virtual_transport = dovecot means it goes to
> master.cf and looks for the dovecot entry and then passes the message
> to it). That would mean postfix is not using vmaps to see if the user
> exists anymore. Instead, it is delegating checking if a user exists to
> dovecot, which is not what I want to do. I want postfix to worry about
> getting mail and making sure the recipient exists. Out of the blue, if
> I replaced the virtual_mailbox entry with local_transport = dovecot,
> or nothing at all, mail is delivered as it should.
>
> My gut feeling is the master.cf dovecot entry is responsible for the
> problem, but I am not sure because I really do not know everything
> that is going on there; this is the first time I venture in that file.
>
> So, could anyone shed some light on what is causing the problem? Thanks!
>