Email Push Service :) smtp+dnotify+Asterisk+... :)

Andreas Kostyrka andreas at
Wed Jan 31 08:00:51 CET 2007

* Elliot F. <elliotf-openmoko-discuss at> [070131 03:45]:
> Robert Michel wrote:
> >Salve,
> >I can't understand why Blackberry and other has become
> >so big into the market, because the server side software
> >for a push service are normal linux admins tools.
> >But wait - the client side need some open programmable
> >devices - like OpenMoko and the Neo1973 :)))
> >When GPRS is always on, than it needs just a emailclient
> >checks regulary every n minutes for new mail - huuuu
> >that's innovation - didn't we used to use this fetching
> >emails from pop, imap or mailboxes since years? (Myself since 1990)
> >Soo I'm not keen in having an email push service,
> >but I'm tired to hear the hype in the news about this.
> >Again, when GPRS is always on, push service is silly
> >buzzword, but what when GPRS is off? Than we can use 1. smtp and some filter to get only the right mails    into /var/mail/rob2neo1973
> >2. dnotify will starts a script when a new file
> >   is in /var/mail/rob2neo1973
> Or you could simply modify the mail server to trigger a script when a message is delivered, rather than having to poll each directory/file.  A procmail/maildrop filter would be one way 
> to implement it easily (allowing you to filter for messages from specific people, to certain folders, etc.)
With the specific problem that you have nowhere to push to. Normal
GPRS has to live with a strict NAT firewall. That's (and because of
billing aspects) probably why pushmailservices usually have their own

> I really like this idea.  As I understood it, many previous "push email" services relied on sending an SMS message to the phone, which made the phone perform the actions that you 
> describe (get new mail.)  However, hooking in directly to the incoming call would save the money that SMS messages cost.

Nope, real push mail is just that. It just needs support from the
network. Or a special low bandwidth protocol to poll.

E.g. one of the highest prices mentioned here was 1KB at 3cent (CDN).
Still, one could design a protocol that sends one "I'm alive byte" say
30 minutes, and listens all the time for an "you've got mail byte".

That would mean, a standby cost of 1KB every 20 days. That's assumming
a keep alive is needed every 30 minutes. Guess it would make sense to
support an additional mode where (for the home network) the phone
senses the right standby before the NAT firewall kills our TCP
connection. (But that should be manual, because the reconnects needed
during probing will use up some KB)

> I'd be interested in seeing/hearing what hooks/services will be exposed.  Will the incoming calls trigger a dbus message or something similar?
> >5. skript2 will switch on GPRS and fetch the new
> >   mail via POP or IMAP
> >   and after downloading the mail it will inform
> >   the user (depend on the dailingprofil)
> >So did I missed something? Why is push services
> >and the software for this such a hype?

Yeah, the original poster missed the fact, that in most billing plans
switching off GPRS is expensive. E.g. GPRS is billed usually in blocks
of 10/100KB (this applies btw also to xMB included plans in Austria).

So switching off GPRS while you've fetched a 2KB email is plain stupid.

> Because it's very handy, and very well integrated.  Blackberry and Windows Mobile (or whatever it's called) have the pieces at both ends that are required for the integration.
Yeah, and the support of the network providers ;)


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