[Dovecot] Capability info in hello message not complete?

[Michal Hlavinka]

On Thursday 01 October 2009 15:15:09 Timo Sirainen wrote:
> On Thu, 2009-10-01 at 14:59 +0200, Michal Hlavinka wrote:
> > Hi,
> >
> > one Fedora user complains about not some troubles after update to dovecot
> > 1.2. He suspects wrong capability information given by dovecot 1.2
> >
> > In dovecot.conf he uses imap_capability= option. While response to 'A
> > CAPABILITY' respects imap_capability value, the capability info in hello
> > message does not.
> >
> > for imap_capability=IMAP4 IMAP4rev1 ACL NAMESPACE CHILDREN SORT QUOTA
> > THREAD=ORDEREDSUBJECT UNSELECT IDLE STARTTLS AUTH=PLAIN
> 
> I suppose he's using Dovecot as a proxy? Because Dovecot doesn't support
> IMAP4 or THREAD=ORDEREDSUBJECT.

yes, dovecot is used as proxy

> 
> > but hello message is:
> > * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE
> > STARTTLS AUTH=PLAIN] Dovecot ready.
> 
> Hmm. Yeah..
> 
> > But it seems even when imap_capability is not used capability in hello
> > message is not complete:
> 
> ..
> 
> > is this expected? Do you think capability information in hello message
> > really can befool clients?
> 
> The capability in greeting message is short on purpose. It's only enough
> capabilities to get client logged in. After login Dovecot sends an
> updated full capability list to the client. It uses a few different
> tricks to get most clients understand the change.
> 
> So the only potential problem I see here is if client understands the
> greeting capability and permanently remembers that the server supports
> LITERAL+, ID and ENABLE after login but the destination server actually
> doesn't. The other capabilities are relevant only before login. I'm not
> entirely sure what, if anything, I should do about this.
> 
> I'd anyway like to hear what exactly is the problem and with what
> client, preferably with IMAP traffic logs showing what's happening
> wrong.

forwarded info:
The imap-server is dbmail which supports "IMAP4 IMAP4rev1 ACL NAMESPACE
CHILDREN SORT QUOTA THREAD=ORDEREDSUBJECT UNSELECT IDLE" and with dovecot 
version 1.1 it worked fine

The problem sue is "LITERAL+" what dbmail does not support.
The problem client was apple iphone