<s>
Microsoft	B-Application
Mail	I-Application
(	O
or	O
MSMail/MSM	O
)	O
was	O
the	O
name	O
given	O
to	O
several	O
early	O
Microsoft	O
e-mail	O
products	O
for	O
local	B-General_Concept
area	I-General_Concept
networks	I-General_Concept
,	O
primarily	O
two	O
architectures	O
:	O
one	O
for	O
Macintosh	O
networks	O
,	O
and	O
one	O
for	O
PC	O
architecture-based	O
LANs	B-General_Concept
.	O
</s>
<s>
All	O
were	O
eventually	O
replaced	O
by	O
the	O
Exchange	B-Operating_System
and	O
Outlook	B-Application
product	O
lines	O
.	O
</s>
<s>
The	O
first	O
Microsoft	B-Application
Mail	I-Application
product	O
was	O
introduced	O
in	O
1988	O
for	O
AppleTalk	B-Application
Networks	O
.	O
</s>
<s>
An	O
MS-DOS	B-Application
client	O
was	O
added	O
for	O
PCs	O
on	O
AppleTalk	B-Application
networks	O
.	O
</s>
<s>
The	O
second	O
Microsoft	B-Application
Mail	I-Application
product	O
,	O
Microsoft	B-Application
Mail	I-Application
for	O
PC	O
Networks	O
v2.1	O
,	O
was	O
introduced	O
in	O
1991	O
.	O
</s>
<s>
It	O
was	O
based	O
on	O
Network	O
Courier	O
,	O
a	O
LAN	B-General_Concept
email	O
system	O
produced	O
by	O
Consumers	O
Software	O
of	O
Vancouver	O
BC	O
,	O
which	O
Microsoft	O
had	O
purchased	O
.	O
</s>
<s>
This	O
version	O
included	O
Microsoft	O
's	O
first	O
Global	O
Address	O
Book	O
technology	O
and	O
first	O
networked	O
scheduling	O
application	O
,	O
Microsoft	B-Application
Schedule+	I-Application
.	O
</s>
<s>
Versions	O
3.0	O
through	O
3.5	O
included	O
email	O
clients	O
for	O
MS-DOS	B-Application
,	O
OS/2	B-Application
1.31	O
,	O
Mac	B-Application
OS	I-Application
,	O
Windows	O
(	O
both	O
16	O
and	O
32-bit	O
)	O
,	O
a	O
separate	O
Windows	O
for	O
Workgroups	O
Mail	O
client	O
,	O
and	O
a	O
DOS-based	O
Remote	O
Client	O
for	O
use	O
over	O
pre-PPP/pre	O
-SLIP	O
dialup	O
modem	B-Application
connections	O
.	O
</s>
<s>
A	O
stripped-down	O
version	O
of	O
the	O
PC-based	O
server	O
,	O
Microsoft	B-Application
Mail	I-Application
for	O
PC	O
Networks	O
,	O
was	O
included	O
in	O
Windows	B-Application
95	I-Application
and	O
Windows	B-Device
NT	I-Device
4.0	I-Device
.	O
</s>
<s>
The	O
last	O
version	O
based	O
on	O
this	O
architecture	O
was	O
3.5	O
;	O
afterwards	O
,	O
it	O
was	O
replaced	O
by	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
Server	I-Operating_System
,	O
which	O
started	O
with	O
version	O
4.0	O
.	O
</s>
<s>
The	O
client	O
software	O
was	O
also	O
named	O
Microsoft	B-Application
Mail	I-Application
,	O
and	O
was	O
included	O
in	O
some	O
older	O
versions	O
of	O
Microsoft	B-Application
Office	I-Application
such	O
as	O
version	O
4.x	O
.	O
</s>
<s>
The	O
original	O
"	O
Inbox	O
"	O
(	O
Exchange	B-Application
client	I-Application
or	O
Windows	B-Application
Messaging	I-Application
)	O
of	O
Windows	B-Application
95	I-Application
also	O
had	O
the	O
capability	O
to	O
connect	O
to	O
an	O
MS	B-Application
Mail	I-Application
server	O
.	O
</s>
<s>
Microsoft	B-Application
Mail	I-Application
Server	O
was	O
eventually	O
replaced	O
by	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
;	O
Microsoft	B-Application
Mail	I-Application
Client	O
,	O
Microsoft	B-Application
Exchange	I-Application
Client	I-Application
,	O
and	O
Schedule+	B-Application
were	O
eventually	O
replaced	O
by	O
Outlook	B-Application
(	O
Windows	O
and	O
Mac	O
)	O
.	O
</s>
<s>
Microsoft	B-Application
Mail	I-Application
was	O
a	O
shared-file	O
mail	O
system	O
;	O
the	O
"	O
postoffice	O
"	O
was	O
a	O
passive	O
database	O
of	O
files	O
which	O
could	O
reside	O
on	O
any	O
file	O
server	O
.	O
</s>
<s>
Clients	O
also	O
acted	O
as	O
Message	B-Protocol
Transfer	I-Protocol
Agents	I-Protocol
(	O
MTAs	O
)	O
for	O
their	O
own	O
postoffices	O
,	O
moving	O
around	O
messages	O
on	O
the	O
postoffice	O
as	O
needed	O
,	O
including	O
queueing	O
messages	O
for	O
outbound	O
delivery	O
to	O
other	O
postoffices	O
,	O
and	O
processing	O
messages	O
queued	O
as	O
arriving	O
from	O
external	O
sources	O
.	O
</s>
<s>
Mail	O
that	O
needed	O
to	O
travel	O
between	O
postoffices	O
were	O
moved	O
by	O
an	O
external	O
MTA	O
called	O
External	O
(	O
external.exe	O
)	O
,	O
which	O
originally	O
ran	O
on	O
MS-DOS	B-Application
.	O
</s>
<s>
A	O
version	O
of	O
External	O
for	O
OS/2	B-Application
1.31	O
was	O
added	O
with	O
Microsoft	B-Application
Mail	I-Application
for	O
PC	O
Networks	O
version	O
3.2	O
,	O
and	O
a	O
multitasking	O
MTA	O
for	O
Windows	O
NT	O
was	O
added	O
with	O
version	O
3.5	O
.	O
</s>
<s>
This	O
ran	O
in	O
the	O
OS/2	B-Application
subsystem	O
of	O
Windows	O
NT	O
and	O
Windows	O
2000	O
,	O
and	O
consisted	O
mostly	O
of	O
the	O
Version	O
3.2a	O
External	O
with	O
wrappers	O
containing	O
hooks	O
allowing	O
control	O
by	O
NT	O
administration	O
utilities	O
.	O
</s>
<s>
Since	O
scheduling	O
data	O
and	O
address	O
lists	O
were	O
also	O
stored	O
locally	O
in	O
these	O
postoffices	O
,	O
moving	O
schedule	O
and	O
global	O
address	O
book	O
information	O
required	O
yet	O
more	O
,	O
separate	O
agents	O
called	O
Dispatch	O
and	O
Microsoft	B-Application
Schedule+	I-Application
Distribution	O
Agent	O
.	O
</s>
<s>
Clients	O
for	O
MS-DOS	B-Application
,	O
dialup	O
,	O
and	O
Mac	B-Application
OS	I-Application
left	O
messages	O
stored	O
on	O
server	O
;	O
the	O
Windows	O
and	O
OS/2	B-Application
clients	O
downloaded	O
the	O
messages	O
instead	O
,	O
using	O
a	O
local	O
file	O
(	O
.MMF	O
)	O
as	O
storage	O
.	O
</s>
<s>
Plans	O
to	O
create	O
a	O
Mac	B-Application
OS	I-Application
client	O
which	O
could	O
access	O
.MMF	O
storage	O
were	O
abandoned	O
before	O
version	O
3.0	O
shipped	O
,	O
though	O
working	O
-	O
if	O
buggy	O
-	O
versions	O
did	O
exist	O
.	O
</s>
<s>
The	O
Windows	O
and	O
OS/2	B-Application
clients	O
were	O
built	O
around	O
an	O
early	O
version	O
of	O
MAPI	B-Protocol
called	O
MAPI	B-Protocol
0	O
,	O
and	O
could	O
in	O
theory	O
enable	O
the	O
client	O
to	O
talk	O
to	O
any	O
server	O
by	O
replacing	O
the	O
MAPI	B-Protocol
DLL	O
with	O
a	O
fully	O
compliant	O
DLL	O
for	O
the	O
appropriate	O
system	O
.	O
</s>
<s>
Unlike	O
the	O
Microsoft	B-Application
Mail	I-Application
3.x	O
server	O
product	O
,	O
the	O
clients	O
could	O
support	O
Bcc	O
:	O
functionality	O
.	O
</s>
<s>
This	O
functionality	O
was	O
not	O
exposed	O
to	O
Microsoft	B-Application
Mail	I-Application
for	O
PC	O
Networks	O
users	O
due	O
to	O
limitations	O
in	O
the	O
server	O
architecture	O
,	O
but	O
the	O
corporate	O
internal	O
MAPI.DLL	O
enabling	O
these	O
particular	O
clients	O
to	O
talk	O
to	O
Xenix-based	O
mail	O
transport	O
systems	O
utilised	O
this	O
functionality	O
.	O
</s>
<s>
The	O
first	O
and	O
almost	O
immediately	O
recalled	O
version	O
of	O
the	O
Microsoft	O
Press	O
book	O
on	O
using	O
Microsoft	B-Application
Mail	I-Application
accidentally	O
used	O
screenshots	O
from	O
the	O
Xenix	O
backend	O
,	O
revealing	O
this	O
concealed	O
capability	O
of	O
the	O
client	O
.	O
</s>
<s>
Microsoft	O
shipped	O
gateways	O
to	O
PROFS	B-Application
,	O
SNADS	B-Architecture
(	O
Office	B-Application
Vision	I-Application
)	O
,	O
SMTP	B-Protocol
,	O
X.400	B-Protocol
over	O
X.25	B-Protocol
,	O
Novell	O
's	O
Message	B-Application
Handling	I-Application
System	I-Application
(	O
MHS	O
)	O
,	O
MCI	O
Mail	O
,	O
AT&T	O
Mail	O
,	O
and	O
others	O
.	O
</s>
<s>
Many	O
companies	O
running	O
these	O
gateways	O
quickly	O
replaced	O
them	O
with	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
Server	I-Operating_System
connectors	O
once	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
4.0	O
shipped	O
.	O
</s>
<s>
In	O
particular	O
an	O
early	O
part	O
of	O
a	O
migration	O
from	O
MSMail	O
to	O
Exchange	B-Operating_System
included	O
replacing	O
the	O
Microsoft	B-Application
Mail	I-Application
for	O
PC	O
Networks	O
Gateway	O
to	O
SMTP	B-Protocol
to	O
the	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
Internet	O
Mail	O
Connector	O
,	O
later	O
renamed	O
to	O
the	O
Microsoft	B-Operating_System
Exchange	I-Operating_System
Internet	O
Mail	O
Service	O
.	O
</s>
<s>
Connection	O
to	O
UUCP-based	O
email	O
systems	O
were	O
supported	O
indirectly	O
,	O
using	O
the	O
Microsoft	B-Application
Mail	I-Application
Gateway	O
to	O
SMTP	B-Protocol
client	O
combined	O
with	O
a	O
Unix	O
system	O
,	O
typically	O
running	O
sendmail	O
as	O
a	O
smarthost	O
.	O
</s>
<s>
SCO	O
Unix	O
and	O
Interactive	O
Unix	O
were	O
both	O
recommended	O
products	O
for	O
this	O
structure	O
,	O
though	O
any	O
SMTP-UUCP	O
smarthost-capable	O
system	O
would	O
work	O
.	O
</s>
