[MlMt] choice of mailserver on osx

[Bill Cole]

On 10 Feb 2016, at 4:17, Marc ARC wrote:

> Dear MM list-users,
>
> We are looking for advice for a good, very functional,  well supported 
>  ( and not to expensive, open source ? ) IMAP-mailserver that runs on 
> OSX

Dovecot is absolutely the IMAP server of choice for just about any 
Unix-like OS where you don't have specialized needs for things it just 
doesn't do. You can install from distribution source yourself or use 
either MacPorts or Homebrew if you prefer or already use one of them for 
software management. OR: see below

> Eventually one that also supports calendar functionality ( CalDAV, . . 
> .)

Yeah, that's a different thing...

MacOS Server (these days a VERY affordable compound app that installs on 
standard MacOS X, not a pricey alternate version of the OS) includes 
slightly customized versions of Dovecot and Postfix with a reasonably 
good working config integrating them AND a CalDAV server that is 
essentially the reference implementation of the CalDAV spec(s). 
Unfortunately the CalDAV specs include some widely-expected extensions 
which seem to confuse implementors on both client and server sides to 
the point where interop really sucks. Mail/calendar integration is the 
worst of it, to the point where both Google and Apple don't even 
seriously try to follow the RFC defining how a CalDAV server should do 
invites and change notifications on their public services. I'm not 
actually sure how well the integration in MacOS X Server is, but it's 
there, it's supported for a low price, and if you prefer a GUI to manage 
a mail server, that's what you're getting. If you prefer managing a mail 
server in a terminal, DO NOT use Server.app: it will punish you for 
fiddling.

If "we" consists of a small number of people (i.e. a family or tiny 
business) you might also want to consider CommuniGatePro, an integrated 
"Universal Communication Server" meant to compare to MS Exchange. It is 
free for a small number of users and functional for more without a 
license except that it tags all outgoing messages with a note that it's 
a trial version when you go over the free limit (I don't recall if it is 
5 or 10 users currently...) Paid pricing for CGP might be deemed "not 
too expensive" in the right frame of reference. Its CalDAV integration 
has evolved over the years from quasi-fraud to pretty solid. CGP is a 
truly integrated server (one closed-source binary daemon for 
SMTP/POP/IMAP/LDAP/SIP/XMPP/CalDAV/CardDAV/WebDAV/etc.) unlike MacOS X 
Server (a couple dozen daemons dressed up in a single duct-taped 
trenchcoat...) or a standalone Dovecot (which is great at IMAP and POP 
but doesn't send or receive mail on its own). Since CGP has a web admin 
GUI you may prefer it over Dovecot's deeply versatile and possibly 
confusing maze of config files or the oversimplified and mandatory GUI 
layer that Server wraps around Dovecot's complexity.

However, mif you really ONLY want IMAP and CalDAV, you can get Dovecot 
in prepackaged or source form and the latest from calendarserver.org and 
wire them together yourself, hooking into the Mac's built-in trivial 
Postfix installation as/if needed. Getting to that state with Server.app 
or CGP would be a lot of pointing and clicking to turn stuff off.

(full disclosure: I make my living in part by managing multiple mail 
systems, which include Postfix+Dovecot, MacOS X Server, and CGP 
environments. They all suck, each in their own special unique ways...)