Freebsd, postfix and push email

Jeffrey Goldberg jeffrey at
Sun Mar 28 21:42:04 UTC 2010

On Mar 28, 2010, at 3:49 PM, krad wrote:

> On 28 March 2010 21:38, Dan Nelson <dnelson at> wrote:
> In the last episode (Mar 28), Ron said:
> > Jeffrey Goldberg wrote:

> > > IMAP, but not POP3, can be used to push, but the iPhone mail client
> > > doesn't support that [...]

> > So how is Mobil Me and Exchange Servers (MS, Zimbra, etc) doing it?

> For ActiveSync at least, the phone has to keep a TCP connection to the
> server open 24/7, and the server sends a notification when a new mail
> arrives.  MobileMe probably works the same way.  The IMAP protocol supports
> a similar "notify on new mail" option, but for some reason Apple doesn't use
> it in their client.

My understanding is that Apple wants all persistent connections to the iPhone to go through them, so that there is only one connection.  This is, putatively, for battery life issues.  Every pushable client on the iPhone doesn't maintain its own TCP connection but works through an API and has to have their service approved by Apple.

Apple made an exception for Exchange so that I could sell iPhones to businesses.

For better information than my possibly misremembered speculation, you would do well to check iPhone developer communities.


Jeffrey Goldberg              

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