At 12:11 AM -0600 9/26/07, Chris Tirpak wrote:
Hello -
I've combed the wiki and archives a bit and can't seem to find what I am lookng for. It seems that BlackBerry Internet server has an issue with IMAP accounts along with IDLE and concurrent connections. Please see the following link (sorry it's fairly long): http://www.blackberry.com/btsc/search.do?cmd=displayKC&docType=kc&externalId=KB13846&sliceId=SAL_Public&dialogID=53398271&stateId=0%200%2027265273
It appears as though IDLE can be implemented without "concurrent connections". Courier appears to do this although they have an option to turn it on. At first blush it seems obvious that any mail server will permit concurrent connections but as I read the docs for Courier and BlackBerry it appears to be a subtle thing whereby IDLE allows more than one connection to IDLE against the same IMAP folder when using maildir.
Does Dovecot support his? Also, if anyone on the list has experience running a BlackBerry against Dovecot, are you currently getting instant (or near instant) notifications? If so what service are you using? T-Mobile?
I am considering upgrading and using Dovecot but BlackBerry support has become critical.
Thanks in advance.
I have just confirmed with a direct test that Dovecot 1.0.0 using Maildir does properly service 2 simultaneous IDLE sessions on the INBOX. I've got my Palm ChatterEmail client logged in and idling and have a manual IMAP session (telnet localhost 143...) and the messages are popping up on the Palm in lockstep with the 'EXISTS' messages kicking out on the telnet session. Meanwhile, Eudora is doing its things from my Mac against the same mailbox (actually tossing messages out of INBOX to other folders) and I'm pretty sure I left Outlook running on my office machine and looking at the same mailbox, so whatever flaky stuff it does is happening on whatever schedule it uses as well...
Note that one strong consideration for IMAP servers with more than a handful of users is going to be dealing with the high concurrency of a lot of eternal connections from the Blackberry server and from other clients latched onto the same mailboxes. I suspect that one reason some systems limit concurrent sessions is that they don't have (or haven't be configured to use) efficient filesystem event monitoring, and the alternatives are quite burdensome. In the case of Courier, it looks like it still relies on SGI's FAM, an abandoned project that doesn't really work well anywhere but Irix and Linux. Dovecot has avoided that at the cost of having to understand each system's unique approach to that issue.
-- Bill Cole bill@scconsult.com