[Dovecot] Not getting new mail notification

[Anand Buddhdev]

Charles Marcus wrote:

>> Unfortunately, the IMAP IDLE extension only works with one mailbox at
>> a time. This is a limitation in the protocol, and both Dovecot and
>> Thunderbird are simply following the protocol. If I remember
>> correctly, Thunderbird only uses IDLE for the INBOX. And while it is
>> using IDLE, it cannot poll the other folders for new mail (well, I
>> suppose it could come out of IDLE, poll all the folders, and go back
>> to IDLE, but it seems like an ugly hack). So you can only use one of
>> 2 modes: either use IDLE, and get notifications of new mail in INBOX
>> only, or use normals periodic polls of all your folders to get
>> notifications of new mail in all of them.
> 
> I may be mistaken, but doesn't 'ENHANCED_IDLE' work with not only
> multiple/concurrent connections to the same folder, but also multiple
> folders?

As far as I know, ENHANCED_IDLE works only with one folder at a time. It
is similar to IDLE, but allows all clients that have the same folder
open, to receive notifications of changes to that folder at the same
time. I think that at the moment, only Courier-IMAP supports it.

In my experience, the only way to get notified of new mail in more than
one folder is poll all the folders regularly. It is ugly, and the more
folders you have the more traffic it generates. Thunderbird makes it
worse by initially selecting each folder (and subfolders) for a poll.
Even a modest numbers of mailboxes will cause a lot of polling,
especially if you check for mail every minute. One has to manually go
and turn off the poll for all the folders where notification is not
needed.

The person who designed the IDLE extension was obviously not thinking
properly. What's the point in having a multi-folder mail access
protocol such as IMAP if the server can't notify the client of changes
in the folders? However, the protocol's designer is rather pig-headed,
and firmly refuses to entertain the idea of IDLE for multiple folders.

-- 
Anand