[Dovecot] RC7: its issues or mine?

Chris Wakelin c.d.wakelin at reading.ac.uk
Mon Aug 21 19:07:22 EEST 2006

David Lee wrote:
> Background:  I'm new to dovecot (although with many years Washington IMAP
> behind me).  We're considering migrating from Washington IMAP to dovecot
> on the main service here, and have just started trying dovecot, using RC7.

We did this last year without the users noticing!

> I have encountered three issues (so far); I'm not sure whether their mine
> or something in dovecot (if the latter, whether bugs or features;
> whether RC7-specific issues; etc.).
> 1. The overall description of "default_mail_env" seems inadequate (in the
> conf file, "doc/variables.txt" and "doc/mail-storages.txt").  I'm trying:
>    default_mail_env = mbox:~:INBOX=/var/spool/mail/%-2.02i/%u:INDEX=/tmp/indexes/%d/%n
> and that seems OK-ish.  (The extra "%-2.02i" is because we subdivide the
> otherwise huge "/var/spool/mail/" directory using the user's uid-mod-100.)
> But the mere act of an IMAP "login" commands creates a directory (empty)
> with the liternal name of ~ (tilde).  (An IMAP 'list "Mail" "*"' command
> successfully finds the usr folders in the 'Mail' subdirectory of the
> user's home directory.)
> It's almost as if the 'default_mail_env' is telling it to create (literal)
> '~' before realising that this is shorthand (as in C-shell) for home
> directory.

Hmm. Could you try using "~/" or "%h" instead of "~"?

> 2. We have some Pine usage in our UNIX cluster.  Historically this has
> taken advantage of the Pine "rsh mailmachine /etc/rimapd" ability to avoid
> the need for the password: pre-authentication etc.  (Yes, we realise that
> 'rsh' has security issues.)  But when I try making symlink "/etc/rimapd"
> point to "/usr/dovecot/sbin/dovecot" this fails:
>    Error: Can't use SSL key file /etc/ssl/private/dovecot.pem: Permission denied

Sounds yucky. I think the program you'd need to run is
"/usr/dovecot/libexec/imap" rather than "dovecot" but you'll need to
supply it some environment variables. I've never tried though.

One thing to watch though, is that you don't have any Pine 3.x users (as
we had!) as it uses obsolete IMAP (v2!) commands not supported by
Dovecot and they would have problems accessing folders.

> 3. I was developing and testing this here at work using an account that I
> mostly use from home using Outlook Express.  I was very careful (I think!)
> only to use the read-only "examine INBOX" command (not "select INBOX").
> When I went home and tried it as usual (connecting to our production
> Washington IMAP service reading that INBOX).  But OE showed all the email
> (including previously read) as "unread" (closed envelope icon).  It seems
> that dovecot has done something to the message headers (even under
> "examine") that has worried OE.  Any thoughts?

Even "select INBOX" shouldn't have changed anything (at least not in
mbox format), so this is very strange. I take it that OE is talking to
the Washington IMAP server. Was OE connected at the time you did the
"examine"? If so, I'd expect Washington to get a bit upset, probably
just losing its "mailbox lock".

> Finally any hints for NFS-based working?  We have a farm of a few Fedora
> machines running the IMAP processes and the sendmail locally-delivery.
> Our current "/etc/fstab" NFS spec. for the INBOX area (on a NetApp) is:
>    rw,noac,actimeo=0,vers=3,tcp,timeo=600,rsize=32768,wsize=32768,hard,intr,fg,nosuid

Not really. I'd guess as long as you include "dotlock" in the lock
options for the MTA and dovecot, it should work OK. You probably don't
need "mmap_disable = yes" as the mail spool is local to Dovecot.

> Any changes?  Issues?  Thinks to consider?  Etc.

Folder subscriptions may need migrating or tweaking and you probably
need to do something with hidden namespaces to deal with the folder prefix.

Hope this helps,

Christopher Wakelin,                           c.d.wakelin at reading.ac.uk
IT Services Centre, The University of Reading,  Tel: +44 (0)118 378 8439
Whiteknights, Reading, RG6 2AF, UK              Fax: +44 (0)118 975 3094

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