[Dovecot] Capability info in hello message not complete?

[Michal Hlavinka]

On Tuesday 06 October 2009 15:35:20 Michal Hlavinka wrote:
> 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.

would it be possible to:
a) send content of imap_capability in greeting message? It should be user's 
responsibility if it's set to something "weird"

b) don't send capability in greeting message if imap_capability is set

c) resurrect login_greeting_capability option

d) something else? :)

> >
> > 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
>