several misc questions, public folders and sharing, quota, ssl

[Aki Tuomi]

> On April 14, 2017 at 3:04 AM David Mehler <dave.mehler at gmail.com> wrote:
> 
> 
> Hello,
> 
> I'm running dovecot 2.29 on a freebsd 10.3 system. I'm wanting to
> optimize how the system is running and have a few misc questions.
> 
> First ssl, is my cipher list good? I'm trying for pfs and wanting to
> ensure these cipherlist is appropriate:
> 
> ssl_cipher_list = EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH
> 

I would add @STRENGTH to the end, so it'll get sorted by strengthness.

> Next, a new feature that I'm trying for is virtual folders that store
> All messages. My understanding of this is that it stores a version of
> every received message in one place? I've got the virtual plugin
> loaded and have:
> 
>   mailbox virtual/All {
>     comment = All my messages
>     special_use = \All
>   }
> 
> I've got a directory /home/vmail/example.com/username/virtual under
> which is an ALL folder both directories are accessible to the vmail
> user, yet there's no contents in this folder and it's showing up
> nowhere.
> 

Configuring virtual all folder:

namespace {
  prefix = virtual
  location = virtual:/etc/dovecot/virtual:INDEX=%h/virtual
  comment = All my messages
  special_use = \All
  mailbox All {
    auto = subscribe
  }
}

==== /etc/dovecot/virtual/All/dovecot-virtual ====
* 
  all
==== EOF ===

> Next, quota warnings, are not being sent at all. I set up a testuser
> with a quota of 2 mb, then sent a message to that user getting the box
> to 95% full, and no message. Took the user overquota with the next
> message, still nothing, and a third message did trigger my custom
> quota exceeded message and the message was bounced.
>

I would recommend you using

mail_plugins = $mail_plugins quota quota_clone

plugin {
  quota = count:User quota
  quota_clone_dict = proxy::sqlquota
  quota_vsizes = true
}

Also,

"Note that the warning is ONLY executed at the exact time when the limit is being crossed, so when you're testing it you have to do it by crossing the limit by saving a new mail. If something else besides Dovecot updates quota so that the limit is crossed, the warning is never executed."

>  I'm wanting to implement public folders. My mailboxes are all
> virtual, and they are stored under /home/vmail/example.com/username
> and /home/vmail/example.org/username in the maildir format. I've got
> one user uid and gid of 999 name of vmail who owns all the mailboxes.
> I've separated out public folders storing them under
> /home/vmail/public. I've created one mailbox called TestFolder and
> new, cur, and tmp directories under it. This is what it looks like:

<snip />
 
> The public/TestFolder is showing up fine and I can switch to it. The
> public/TestFolder1 is not showing up at all so I'm not seeing it and
> can't switch to it. Any ideas?
> 

Not sure why it's not showing up, *but*, you could add :INDEXPVT=%h/public to the folder, to keep per-user indexes separate.

> My second question involves public folders and domain sharing. Are
> public folders accessible to all users and all domains? I've got two
> domains example.com and example.org i'd like to create a folder that
> some users in example.com can share with some users in example.org,
> not necessarily all users in those domains should be able to see the
> folders.
> 

Dovecot does not, as per such, care about your domains. It cares about user names. If you want to do this kind of thing, please consult ACL plugin. https://wiki2.dovecot.org/ACL

> Ideas welcome.
> 
> Thanks.
> Dave.
> 

Some other comments, if you are using SSL, you can drop cram-md5 as auth mech, it's not storage-safe.

you should use mail_location = maildir:~/maildir:LAYOUT=fs

to avoid your other things in user's home being interprepted as mail directories.

why are you setting these?
maildir_broken_filename_sizes = yes
maildir_empty_new = yes
maildir_very_dirty_syncs = yes

and in general I see lots of overconfiguring, dovecot defaults are usually right, and setting various things just for the fun of it, can cause problems.

Aki