[Dovecot] namespaces...

Jack Stewart jstewart at caltech.edu
Fri Aug 22 22:36:43 EEST 2008


John Doe wrote:
> Hi,
> 
> I am new to dovecot and I am a bit confused with how namespaces/prefixes/separators are handled by the clients and dovecot...
> I tried to understand the desciption from the conf file but without success.
> 
> With each conf I create the following path /f1/f2 on the client (thunderbird) and get the following on the dovecot server:
> 
>   PREFIX= and separator=/  => .INBOX.f1.f2 + .INBOXTrash
>   PREFIX=INBOX/ and separator=/  => .f1.f2 and no Trash
>  
> PREFIX=INBOX. and separator=.  => .f1.f2 and no Trash
> 
> Could someone point me to some IMAP for dummy web page...?  ;D
> Or, what is the best conf able to handle most clients?
> 
> Thx,
> JD
> 

I research a similar issue for a user and found that the / character is 
not allowed (or at least didn't used to be) in folder names. Even if you 
can get it to work on the server, a lot of clients will break. In fact 
various clients seem to be sensitive to what characters you use outside 
of a limited range.

The SEPARATOR should just refer to the storage structure and the PREFIX 
should refer to the hierarchy. So if you use "/" as your SEPARATOR, then 
your storage structure will be user-directory/folder/sub-folder and if 
you use "." as your storage structure (the default), then your storage 
structure will be user-directory/.folder.sub-folder . A PREFIX of INBOX. 
should cause all of the folders & sub-folders to appear under the inbox; 
a PREFIX of "." should cause all of the folders to appear at the top 
level; and a PREFIX of Mail. will should all of the folders to appear 
under Mail with the exception of the INBOX.

The reason that I use the word should because not all clients care what 
you declare the namespace to be. They "know", or think they know, 
better. Webmail is one of these clients as you declare your own prefix 
in the configuration file.

Once you decide on what structure you want, make sure that your 
configuration will make that structure the default as you can run with 
multiple namespace in the same storage locations (if you are a 
masochist). The sample configuration and wiki is pretty good on this 
part but let me know if you want help. I was a masochist for a while in 
my development environment until I became smarter.

The RFC isn't a great read so you might want to look at the following 
discussions about folder characters:

http://support.microsoft.com/kb/281211
http://lists.apple.com/archives/macos-x-server/2005/dec/msg00445.html
http://osdir.com/ml/mail.squirrelmail.internationalization/2005-10/msg00041

The ideal hierarchy seems client dependent for the clients that care.

My preference is to the INBOX. prefix because that's what my ISP and 
(yuck) Exchange uses. So we can the same look and feel to give our users 
the warm fuzzy. I'm also lazy and our support staff want the minimum of 
pain. Applemail seems happy with this setup, unless you have more than 
one account in which case it gets grumpy no matter what. Thunderbird, 
pine, and mutt all seem good but they are pretty flexible. I make other 
people test Microsoft.

We are currently using Mail. in production for legacy reasons but that 
will sort of change someday (we give both depending on server address).

I think that Timo likes the (default) top level structure but that is 
very scary in my environment.

I wish I had a better answer but at the end of the day your 
configuration depends on your client base and what works best for your 
server.

Hope this helps - sorry about the length.

---Jack

--
Jack Stewart
jstewart at caltech.edu
http://www.imss.caltech.edu



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