I can’t count the number of times recently that people have told me that they are about to or just have purchased a Blackberry just so that they could have the all important, critical to business, world goes dark without, feature of “push email“. As a Nokia E61i smartphone user, I have the ability to install “Blackberry” support, as well as MS Exchange “Direct Push” support (Available in Exchange Server 2003 and later) but the feature that I actually use is trusty old IMAP! Yes, ladies and gentlemen, the Internet Message Access Protocol (known as IMAP to most of us) has had “push email” ever since the IBM T.J. Watson Research Center published RFC2177 in June 1997. I guarantee that this is WAAAAAY before anyone reading this had either a “smart phone” or had heard of “push email”.
The IDLE command is sent from the client to the server when the client is ready to accept unsolicited mailbox update messages. The server requests a response to the IDLE command using the continuation (“+”) response. The IDLE command remains active until the client responds to the continuation, and as long as an IDLE command is active, the server is now free to send untagged EXISTS, EXPUNGE, and other messages at any time.
What this means is that your IMAP mail client (Including desktop applications like Thunderbird) can connect to the server, ask for a current list of mail, then wait for the server to send it updates whenever something new arrives. I am using this to great effect between my E61i and my openSUSE Linux based Dovecot mail server which notifies within 1 second of any new mail… Due to GPRS delays, that may sometimes take 2-3 seconds before the mail actually hits the phone, which is about the time it takes you to get the phone out of your pocket…
Yep, thats right, download a free copy of openSUSE, install Dovecot and have “push email” using technology developed 10 years ago on your industry standard Nokia (or Sony Ericsson) IMAP supporting phone. It makes you wonder why people pay tens of thousands of dollars for Blackberry Enterprise Server doesn’t it… In my opinion, whatever Blackberry pay to their marketing department is way too little… They could sell ice to eskimos!