> Hi all,
>
> After getting fedup with the dovecot 2.3 to 2.4 migration pain, and
> the annoying aspects of setting up DKIM with postfix properly, I've
This was a terrible upgrade, because some features just stopped
working altogether -- the main issue remaining for us being Lazy
Expunge (which I now have partly working, but it's not working
correctly enough as it loses folder structure data, so we still can't
use it).
We like Dovecot very much because it's fast and low on resources
(which is important when serving tens of thousands of IMAP4 users).
We also find that Dovecot 2.4 is noticeably faster than 2.3 for users
with folders of more than 5,000 messages (especially INBOX), has
faster authentication (which relies on a PostgreSQL backend), and
only a slight increase in per-connection memory usage. (Dovecot 2.3
already provided excellent performance, so in this regard, to us 2.4
brings major optimizations to the right areas.)
There were so many changes introduced in Dovecot 2.4 that were so
significant that I believe it deserved a major version increment to
Dovecot 3 (or 4 since a specialized version 3 already exists). These
major changes broke a lot of things, and we still ran into some
subtle issues after first working it through a test environment
(which had time-constraints that limited testing efforts).
For the DMARC, DKIM, ARC, and SPF functionality, I moved all of this
out of Postfix with multiple milters (one of which was intermittently
failing to handle certain complex SPF configurations), and into just
one rspamd milter, which integrates everything neatly, and presents
DMARC/DKIM/ARC/SPF together in a multi-line SMTP header set -- this
makes it so much easier to work with now.
Into rspamd we also moved SpamAssassin, and have it handling
whitelists, blacklists, greylisting, etc., all of which further
simplifies our Postfix configuration (leaving Postfix to do all of
its excellent things well whilst reducing milter callouts to 1). Our
finding is that rspamd is flexible, competent, and efficient in
handling all of these functions.
> been thinking about moving my personal domain to using either
> mail-in-a-box (https://mailinabox.email/) or Stalwart
> (https://stalw.art/) and I'm leaning towards Stalwart if only because
> it's not as draconian about DNS control.
>
> So... has anyone else deployed it and how do you feel about it?
I've never used Stalwart, so I don't have any perspective to share
on it. Moving to a different POP3/IMAP4 server will require a lot of
planning and testing (which gets more complicated if it doesn't use
the same Maildir++ format that we're using in Dovecot), and it's just
not in the cards for us at this point as we have other priorities.
So, we're happy to continue to use Postfix with rspamd and
SpamAssassin (plus our own Perl scripts that add customizations and
some subtle enhancements during the before-queue filter stage) with
Dovecot on Debian Linux, as these solutions have proven to us for
decades that they are reliable at handling heavy demands from large
numbers of users (scaling beyond the infamous 10k problem).
--
Postmaster - [email protected]
Randolf Richardson, CNA - [email protected]
Inter-Corporate Computer & Network Services, Inc.
Vancouver, Beautiful British Columbia, Canada
https://www.inter-corporate.com/
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