<s>
Messenger	B-Protocol
service	O
is	O
a	O
network-based	O
system	O
notification	O
Windows	O
service	O
by	O
Microsoft	O
that	O
was	O
included	O
in	O
some	O
earlier	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
This	O
retired	O
technology	O
,	O
although	O
it	O
has	O
a	O
similar	O
name	O
,	O
is	O
not	O
related	O
in	O
any	O
way	O
to	O
the	O
later	O
,	O
Internet-based	O
Microsoft	O
Messenger	B-Protocol
service	O
for	O
instant	O
messaging	B-Protocol
or	O
to	O
Windows	B-Application
Messenger	I-Application
and	O
Windows	B-Protocol
Live	I-Protocol
Messenger	I-Protocol
(	O
formerly	O
named	O
MSN	B-Protocol
Messenger	I-Protocol
)	O
client	O
software	O
.	O
</s>
<s>
WinPopup	B-Protocol
sends	O
messages	O
from	O
one	O
Windows	O
computer	O
to	O
another	O
on	O
the	O
same	O
LAN	B-General_Concept
.	O
</s>
<s>
It	O
is	O
available	O
in	O
all	O
Windows	O
versions	O
from	O
Windows	O
for	O
Workgroups	O
3.1	O
to	O
Windows	B-Device
Me	I-Device
,	O
but	O
has	O
never	O
been	O
included	O
with	O
Windows	O
NT-based	O
operating	O
systems	O
.	O
</s>
<s>
WinPopup	B-Protocol
works	O
by	O
means	O
of	O
the	O
NetBEUI	B-Protocol
protocol	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
port	O
to	O
Linux	B-Application
with	O
an	O
extended	O
feature	O
called	O
LinPopUp	O
,	O
which	O
allows	O
adding	O
Linux	B-Application
computers	O
to	O
the	O
set	O
.	O
</s>
<s>
Linpopup	O
is	O
an	O
X	B-Operating_System
Window	I-Operating_System
graphical	O
port	O
of	O
Winpopup	B-Protocol
,	O
and	O
a	O
package	O
for	O
Debian	O
linux	B-Application
.	O
</s>
<s>
It	O
runs	O
over	O
Samba	B-Language
.	O
</s>
<s>
The	O
traditional	O
Unix	O
functional	O
equivalent	O
of	O
WinPopUp	B-Protocol
would	O
be	O
the	O
wall	O
and	O
write	O
commands	O
.	O
</s>
<s>
The	O
Messenger	B-Protocol
Service	O
was	O
originally	O
designed	O
for	O
use	O
by	O
system	O
administrators	O
to	O
notify	O
Windows	O
users	O
about	O
their	O
networks	O
.	O
</s>
<s>
It	O
was	O
used	O
maliciously	O
to	O
present	O
pop-up	O
advertisements	O
to	O
users	O
over	O
the	O
Internet	O
(	O
by	O
using	O
mass-messaging	O
systems	O
which	O
sent	O
a	O
desired	O
message	O
to	O
a	O
specified	O
range	O
of	O
IP	B-Protocol
addresses	I-Protocol
)	O
.	O
</s>
<s>
Even	O
though	O
Windows	B-Application
XP	I-Application
included	O
a	O
firewall	B-Application
,	O
it	O
was	O
not	O
enabled	O
by	O
default	O
.	O
</s>
<s>
As	O
a	O
result	O
of	O
this	O
abuse	O
,	O
the	O
Messenger	B-Protocol
Service	O
was	O
disabled	O
by	O
default	O
in	O
Windows	B-Application
XP	I-Application
Service	O
Pack	O
2	O
.	O
</s>
<s>
The	O
Messenger	B-Protocol
Service	O
was	O
discontinued	O
in	O
Windows	B-Application
Vista	I-Application
and	O
Windows	B-Device
Server	I-Device
2008	I-Device
and	O
replaced	O
by	O
the	O
old	O
MSG.exe	O
.	O
</s>
<s>
The	O
Messenger	B-Protocol
service	O
in	O
Windows	B-Application
2000	I-Application
and	O
Windows	B-Application
XP	I-Application
uses	O
the	O
NetBIOS	B-Protocol
over	O
TCP/IP	O
(	O
NetBT	O
)	O
protocol	O
.	O
</s>
<s>
The	O
alternative	O
way	O
to	O
send	O
a	O
message	O
is	O
to	O
write	O
it	O
to	O
a	O
MailSlot	B-Operating_System
named	O
messngr	O
.	O
</s>
<s>
It	O
requires	O
UDP	B-Protocol
ports	I-Protocol
135	O
,	O
137	O
,	O
and	O
138	O
and	O
TCP	B-Protocol
ports	I-Protocol
135	O
,	O
139	O
,	O
and	O
445	O
to	O
work	O
.	O
</s>
<s>
In	O
Windows	B-Device
NT	I-Device
3.5	I-Device
,	O
NT	B-Device
3.51	I-Device
and	O
NT	B-Device
4.0	I-Device
,	O
Messenger	B-Protocol
used	O
the	O
older	O
NetBIOS	B-Protocol
protocol	O
.	O
</s>
<s>
(	O
NetBIOS	B-Protocol
is	O
not	O
installed	O
with	O
Windows	B-Application
2000	I-Application
.	O
)	O
</s>
<s>
Messenger	B-Protocol
service	O
can	O
be	O
used	O
by	O
either	O
Net	B-Protocol
Send	I-Protocol
command	O
from	O
a	O
command-line	O
interface	O
.	O
</s>
<s>
In	O
addition	O
,	O
the	O
Alerter	O
service	O
uses	O
Messenger	B-Protocol
to	O
send	O
administrative	O
alerts	O
to	O
network	O
subscribers	O
.	O
</s>
