<s>
Direct	B-Operating_System
Push	I-Operating_System
is	O
Microsoft	O
's	O
technology	O
for	O
receiving	O
e-mail	O
instantly	O
on	O
Windows	B-Operating_System
Mobile	I-Operating_System
5.0	O
,	O
6.0	O
and	O
6.1	O
enabled	O
devices	O
,	O
from	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
Servers	I-Operating_System
,	O
Kerio	B-Protocol
Connect	I-Protocol
and	O
Zarafa	B-Protocol
.	O
</s>
<s>
It	O
provides	O
response	O
times	O
similar	O
to	O
the	O
push	B-General_Concept
technology	I-General_Concept
of	O
RIM	O
's	O
BlackBerry	B-Operating_System
service	O
,	O
but	O
needs	O
no	O
special	O
server	O
upgrades	O
other	O
than	O
having	O
Exchange	B-Operating_System
Server	I-Operating_System
2003	O
Service	O
Pack	O
2	O
.	O
</s>
<s>
It	O
works	O
by	O
initiating	O
an	O
HTTPS	O
connection	O
to	O
the	O
server	O
through	O
any	O
connectivity	O
that	O
can	O
carry	O
an	O
IP	O
traffic	O
such	O
as	O
GPRS	B-General_Concept
or	O
EDGE	O
technologies	O
,	O
through	O
the	O
firewall	O
,	O
then	O
a	O
front-end	O
server	O
that	O
connects	O
to	O
the	O
Exchange	B-Operating_System
server	I-Operating_System
that	O
hosts	O
the	O
user	O
mailbox	O
.	O
</s>
<s>
It	O
also	O
eliminates	O
the	O
need	O
for	O
devices	O
to	O
have	O
a	O
dedicated	B-Protocol
IP	I-Protocol
address	I-Protocol
,	O
but	O
requires	O
"	O
Always	O
on	O
"	O
GPRS	B-General_Concept
or	O
3G	B-Architecture
connection	O
.	O
</s>
<s>
The	O
Direct	B-Operating_System
Push	I-Operating_System
technology	O
served	O
as	O
a	O
feature	O
for	O
the	O
Exchange	B-Operating_System
Server	I-Operating_System
ActiveSync	O
service	O
,	O
which	O
allowed	O
Windows	B-Operating_System
Mobile	I-Operating_System
5.0	O
and	O
later	O
versions	O
of	O
Windows	B-Operating_System
Mobile	I-Operating_System
software	I-Operating_System
to	O
keep	O
their	O
data	O
up-to-date	O
.	O
</s>
