Freebsd, postfix and push email

krad kraduk at
Sun Mar 28 20:49:45 UTC 2010

On 28 March 2010 21:38, Dan Nelson <dnelson at> wrote:

> In the last episode (Mar 28), Ron said:
> > Jeffrey Goldberg wrote:
> > > On Mar 28, 2010, at 1:36 AM, perryh at wrote:
> > >> Er, no.  POP3 and IMAP are "pull" services, wherein the client polls
> > >> the server periodically for any newly-arrived messages.
> > >
> > > IMAP, but not POP3, can be used to push, but the iPhone mail client
> > > doesn't support that as far as I know.  It does support being pushed to
> > > over Mobile Me, but not on regular IMAP.
> >
> > So how is Mobil Me and Exchange Servers (MS, Zimbra, etc) doing it?
> > That's what I'd like to replicate on my FreeBsd server.  This seems to be
> > a well guarded secret I'd like to crack.
> >
> > On the iPhone, at least, the phone is not polling the servers, some kind
> > of message (SMS?) is being sent to the phone that makes it put a little
> > red badge on the corner of the mail app icon telling it how many messages
> > are waiting.  The messages don't seem to be download during the push,
> it's
> > just a count (I could be wrong about this).
> 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.
> --
>        Dan Nelson
>        dnelson at
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To totally confuse thin most modern mtas can easily be configured to pipe
mails to an external program or pipe. This can then to whatever, include
pushing stuff to a mobile phone I would imagine.

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