<s>
Internet	B-Application
Information	I-Application
Services	I-Application
(	O
IIS	O
)	O
is	O
an	O
extensible	O
web	B-Application
server	I-Application
created	O
by	O
Microsoft	O
for	O
use	O
with	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
.	O
</s>
<s>
IIS	O
supports	O
HTTP	B-Protocol
,	O
HTTP/2	B-Protocol
,	O
HTTPS	B-Protocol
,	O
FTP	B-Protocol
,	O
FTPS	B-Protocol
,	O
SMTP	B-Protocol
and	O
NNTP	B-Protocol
.	O
</s>
<s>
It	O
has	O
been	O
an	O
integral	O
part	O
of	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
since	O
Windows	B-Device
NT	I-Device
4.0	I-Device
,	O
though	O
it	O
may	O
be	O
absent	O
from	O
some	O
editions	O
(	O
e.g.	O
</s>
<s>
The	O
first	O
Microsoft	O
web	B-Application
server	I-Application
was	O
a	O
research	O
project	O
at	O
the	O
European	O
Microsoft	B-Device
Windows	I-Device
NT	I-Device
Academic	O
Centre	O
(	O
EMWAC	O
)	O
,	O
part	O
of	O
the	O
University	O
of	O
Edinburgh	O
in	O
Scotland	O
,	O
and	O
was	O
distributed	O
as	O
freeware	B-License
.	O
</s>
<s>
However	O
,	O
since	O
the	O
EMWAC	O
server	O
was	O
unable	O
to	O
handle	O
the	O
volume	O
of	O
traffic	O
going	O
to	O
Microsoft.com,	O
Microsoft	O
was	O
forced	O
to	O
develop	O
its	O
own	O
web	B-Application
server	I-Application
,	O
IIS	O
.	O
</s>
<s>
IIS	O
1.0	O
was	O
initially	O
released	O
as	O
a	O
free	O
add-on	O
for	O
Windows	B-Device
NT	I-Device
3.51	O
.	O
</s>
<s>
IIS	O
2.0	O
was	O
included	O
with	O
Windows	B-Device
NT	I-Device
4.0	I-Device
.	O
</s>
<s>
IIS	O
3.0	O
,	O
which	O
was	O
included	O
with	O
Service	O
Pack	O
2	O
of	O
Windows	B-Device
NT	I-Device
4.0	I-Device
,	O
introduced	O
the	O
Active	B-General_Concept
Server	I-General_Concept
Pages	I-General_Concept
dynamic	O
scripting	O
environment	O
.	O
</s>
<s>
IIS	O
4.0	O
was	O
released	O
as	O
part	O
of	O
the	O
"	O
Option	O
Pack	O
"	O
for	O
Windows	B-Device
NT	I-Device
4.0	I-Device
.	O
</s>
<s>
It	O
introduced	O
the	O
new	O
MMC-based	O
administration	O
application	O
and	O
also	O
was	O
the	O
first	O
version	O
where	O
you	O
can	O
run	O
multiple	O
instances	O
of	O
web	O
and	O
FTP	B-Protocol
servers	I-Protocol
,	O
differentiating	O
them	O
by	O
port	O
number	O
and/or	O
hostname	O
.	O
</s>
<s>
IIS	O
5.0	O
shipped	O
with	O
Windows	O
2000	O
and	O
introduced	O
additional	O
authentication	O
methods	O
,	O
support	O
for	O
the	O
WebDAV	B-Protocol
protocol	O
,	O
and	O
enhancements	O
to	O
ASP	B-General_Concept
.	O
</s>
<s>
IIS	O
5.0	O
also	O
dropped	O
support	O
for	O
the	O
Gopher	B-Protocol
protocol	I-Protocol
.	O
</s>
<s>
IIS	O
5.0	O
added	O
HTTP.SYS	O
.	O
</s>
<s>
IIS	O
6.0	O
included	O
with	O
Windows	B-Application
Server	I-Application
2003	I-Application
and	O
Windows	B-Operating_System
XP	I-Operating_System
Professional	I-Operating_System
x64	I-Operating_System
Edition	I-Operating_System
,	O
added	O
support	O
for	O
IPv6	B-Protocol
and	O
included	O
a	O
new	O
worker	O
process	O
model	O
that	O
increased	O
security	O
as	O
well	O
as	O
reliability	O
.	O
</s>
<s>
HTTP.sys	O
was	O
introduced	O
in	O
IIS	O
6.0	O
as	O
an	O
HTTP-specific	O
protocol	O
listener	O
for	O
HTTP	B-Protocol
requests	I-Protocol
.	O
</s>
<s>
Also	O
each	O
component	O
(	O
like	O
for	O
example	O
Server	O
Side	O
Includes	O
or	O
ASP	B-General_Concept
)	O
now	O
has	O
to	O
be	O
explicitly	O
installed	O
,	O
because	O
in	O
earlier	O
versions	O
often	O
hackers	O
entered	O
sites	O
by	O
using	O
security	O
bugs	O
of	O
components	O
that	O
were	O
not	O
even	O
in	O
use	O
by	O
the	O
hacked	O
site	O
,	O
improving	O
security	O
.	O
</s>
<s>
IIS	O
7.0	O
was	O
a	O
complete	O
redesign	O
and	O
rewrite	O
of	O
IIS	O
and	O
was	O
shipped	O
with	O
Windows	B-Application
Vista	I-Application
and	O
Windows	B-Device
Server	I-Device
2008	I-Device
.	O
</s>
<s>
It	O
also	O
introduced	O
a	O
hierarchical	O
configuration	O
system	O
allowing	O
for	O
simpler	O
site	O
deploys	O
,	O
a	O
new	O
Windows	O
Forms-based	O
management	O
application	O
,	O
new	O
command-line	O
management	O
options	O
and	O
increased	O
support	O
for	O
the	O
.NET	B-Application
Framework	I-Application
.	O
</s>
<s>
IIS	O
7.0	O
on	O
Vista	B-Application
does	O
not	O
limit	O
the	O
number	O
of	O
allowed	O
connections	O
as	O
IIS	O
on	O
XP	O
did	O
,	O
but	O
limits	O
concurrent	O
requests	O
to	O
10	O
(	O
Windows	B-Application
Vista	I-Application
Ultimate	O
,	O
Business	O
,	O
and	O
Enterprise	O
Editions	O
)	O
or	O
3	O
(	O
Vista	B-Application
Home	O
Premium	O
)	O
.	O
</s>
<s>
IIS	O
7.5	O
was	O
included	O
in	O
Windows	B-Device
7	I-Device
(	O
but	O
it	O
must	O
be	O
turned	O
on	O
in	O
the	O
side	O
panel	O
of	O
Programs	O
and	O
Features	O
)	O
and	O
Windows	B-Device
Server	I-Device
2008	I-Device
R2	I-Device
.	O
</s>
<s>
IIS	O
7.5	O
improved	O
WebDAV	B-Protocol
and	O
FTP	B-Protocol
modules	O
as	O
well	O
as	O
command-line	O
administration	O
in	O
PowerShell	B-Application
.	O
</s>
<s>
It	O
also	O
introduced	O
TLS	B-Protocol
1.1	O
and	O
TLS	B-Protocol
1.2	O
support	O
and	O
the	O
Best	O
Practices	O
Analyzer	O
tool	O
and	O
process	O
isolation	O
for	O
application	O
pools	O
.	O
</s>
<s>
IIS	O
8.0	O
is	O
only	O
available	O
in	O
Windows	B-Device
Server	I-Device
2012	I-Device
and	O
Windows	B-Application
8	I-Application
.	O
</s>
<s>
IIS	O
8.0	O
includes	O
SNI	B-Protocol
(	O
binding	O
SSL	O
to	O
hostnames	O
rather	O
than	O
IP	O
addresses	O
)	O
,	O
Application	O
Initialization	O
,	O
centralized	O
SSL	O
certificate	O
support	O
,	O
and	O
multicore	O
scaling	O
on	O
NUMA	B-Operating_System
hardware	O
,	O
among	O
other	O
new	O
features	O
.	O
</s>
<s>
IIS	O
8.5	O
is	O
included	O
in	O
Windows	B-Device
Server	I-Device
2012	I-Device
R2	O
and	O
Windows	B-Device
8.1	I-Device
.	O
</s>
<s>
version	O
10.0.14393	O
is	O
included	O
in	O
Windows	B-Device
Server	I-Device
2016	I-Device
released	O
2016-09-26	O
and	O
Windows	O
10	O
Anniversary	O
Update	O
released	O
2016-08-02	O
.	O
</s>
<s>
This	O
version	O
includes	O
support	O
for	O
HTTP/2	B-Protocol
,	O
running	O
IIS	O
in	O
Windows	O
containers	O
on	O
Nano	O
Server	O
,	O
a	O
new	O
Rest	O
management	O
API	O
and	O
corresponding	O
web-based	O
management	O
GUI	O
,	O
and	O
Wildcard	O
Host	O
Headers	O
.	O
</s>
<s>
IIS	O
10.0	O
version	O
1709	O
is	O
included	O
in	O
Windows	B-Device
Server	I-Device
,	O
version	O
1709	O
(	O
Semi-Annual	O
Channel	O
)	O
and	O
Windows	O
10	O
Fall	O
Creators	O
Update	O
both	O
released	O
2017-10-17	O
.	O
</s>
<s>
This	O
version	O
adds	O
support	O
for	O
HSTS	B-Protocol
,	O
container	O
enhancements	O
,	O
new	O
site	O
binding	O
PowerShell	B-Application
cmdlets	O
,	O
and	O
4	O
new	O
server	O
variables	O
prefixed	O
with	O
"	O
CRYPT_	O
"	O
.	O
</s>
<s>
version	O
10.0.17763	O
is	O
included	O
in	O
Windows	B-Device
Server	I-Device
2019	I-Device
and	O
Windows	O
10	O
October	O
Update	O
released	O
2018-10-02	O
.	O
</s>
<s>
This	O
version	O
added	O
flags	O
for	O
control	O
of	O
HTTP/2	B-Protocol
and	O
OCSP	B-Protocol
Stapling	I-Protocol
per	O
site	O
,	O
a	O
compression	O
API	O
and	O
implementing	O
module	O
supporting	O
both	O
gzip	B-Application
and	O
brotli	B-Application
schemes	O
,	O
and	O
a	O
UI	O
for	O
configuring	O
HSTS	B-Protocol
.	O
</s>
<s>
Microsoft	O
was	O
criticized	O
by	O
vendors	O
of	O
other	O
web	B-Application
server	I-Application
software	O
,	O
including	O
O'Reilly	O
&	O
Associates	O
and	O
Netscape	B-Protocol
,	O
for	O
its	O
licensing	O
of	O
early	O
versions	O
of	O
Windows	B-Device
NT	I-Device
;	O
the	O
"	O
Workstation	O
"	O
edition	O
of	O
the	O
OS	O
permitted	O
only	O
ten	O
simultaneous	O
TCP/IP	O
connections	O
,	O
whereas	O
the	O
more	O
expensive	O
"	O
Server	O
"	O
edition	O
,	O
which	O
otherwise	O
had	O
few	O
additional	O
features	O
,	O
permitted	O
unlimited	O
connections	O
but	O
bundled	O
IIS	O
.	O
</s>
<s>
It	O
was	O
implied	O
that	O
this	O
was	O
intended	O
to	O
discourage	O
consumers	O
from	O
running	O
alternative	O
web	B-Application
server	I-Application
packages	O
on	O
the	O
cheaper	O
edition	O
.	O
</s>
<s>
Netscape	B-Protocol
wrote	O
an	O
open	O
letter	O
to	O
the	O
Antitrust	O
Division	O
of	O
the	O
U.S.	O
Department	O
of	O
Justice	O
regarding	O
this	O
distinction	O
in	O
product	O
licensing	O
,	O
which	O
it	O
asserted	O
had	O
no	O
technical	O
merit	O
.	O
</s>
<s>
O'Reilly	O
showed	O
that	O
the	O
user	O
could	O
remove	O
the	O
enforced	O
limits	O
meant	O
to	O
cripple	O
NT	B-Device
4.0	I-Device
Workstation	O
as	O
a	O
web	B-Application
server	I-Application
with	O
two	O
registry	O
key	O
changes	O
and	O
other	O
trivial	O
configuration	O
file	O
tweaking	O
.	O
</s>
<s>
IIS	B-Application
7	I-Application
includes	O
native	O
modules	O
as	O
part	O
of	O
the	O
full	O
installation	O
.	O
</s>
<s>
Authentication	O
changed	O
slightly	O
between	O
IIS	O
6.0	O
and	O
IIS	B-Application
7	I-Application
,	O
most	O
notably	O
in	O
that	O
the	O
anonymous	O
user	O
which	O
was	O
named	O
"IUSR_{machinename}"	O
is	O
a	O
built-in	O
account	O
in	O
Vista	B-Application
and	O
future	O
operating	O
systems	O
and	O
named	O
"	O
IUSR	O
"	O
.	O
</s>
<s>
Notably	O
,	O
in	O
IIS	B-Application
7	I-Application
,	O
each	O
authentication	O
mechanism	O
is	O
isolated	O
into	O
its	O
own	O
module	O
and	O
can	O
be	O
installed	O
or	O
uninstalled	O
.	O
</s>
<s>
ASP.NET	B-Application
4.5	O
support	O
:	O
With	O
IIS	O
8.0	O
,	O
ASP.NET	B-Application
4.5	O
is	O
included	O
by	O
default	O
,	O
and	O
IIS	O
also	O
offers	O
several	O
configuration	O
options	O
for	O
running	O
it	O
side	O
by	O
side	O
with	O
ASP.NET	B-Application
3.5	O
.	O
</s>
<s>
Multicore	O
scaling	O
on	O
NUMA	B-Operating_System
hardware	O
:	O
IIS	O
8.0	O
provides	O
several	O
configuration	O
options	O
that	O
optimize	O
performance	O
on	O
systems	O
that	O
run	O
NUMA	B-Operating_System
,	O
such	O
as	O
running	O
several	O
worker	O
processes	O
under	O
one	O
application	O
pool	O
,	O
using	O
soft	O
or	O
hard	O
affinity	O
and	O
more	O
.	O
</s>
<s>
Server	B-Protocol
Name	I-Protocol
Indication	I-Protocol
(	O
SNI	B-Protocol
)	O
:	O
SNI	B-Protocol
is	O
an	O
extension	O
to	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
,	O
which	O
allows	O
the	O
binding	O
of	O
multiple	O
websites	O
with	O
different	O
hostnames	O
to	O
one	O
IP	O
address	O
(	O
similar	O
to	O
how	O
Host	O
Headers	O
are	O
used	O
for	O
non-SSL	O
sites	O
)	O
.	O
</s>
<s>
IIS	O
Express	O
,	O
a	O
lightweight	O
(	O
4.5	O
–	O
6.6	O
MB	O
)	O
version	O
of	O
IIS	O
,	O
is	O
available	O
as	O
a	O
standalone	O
freeware	B-License
server	O
and	O
may	O
be	O
installed	O
on	O
Windows	O
XP	O
with	O
Service	O
Pack	O
3	O
and	O
subsequent	O
versions	O
of	O
Microsoft	O
Windows	O
.	O
</s>
<s>
IIS	O
7.5	O
Express	O
supports	O
only	O
the	O
HTTP	B-Protocol
and	O
HTTPS	B-Protocol
protocols	O
.	O
</s>
<s>
It	O
is	O
portable	O
,	O
stores	O
its	O
configuration	O
on	O
a	O
per-user	O
basis	O
,	O
does	O
not	O
require	O
administrative	O
privileges	O
and	O
attempts	O
to	O
avoid	O
conflicting	O
with	O
existing	O
web	B-Application
servers	I-Application
on	O
the	O
same	O
machine	O
.	O
</s>
<s>
IIS	O
Express	O
can	O
be	O
downloaded	O
separately	O
or	O
as	O
a	O
part	O
of	O
WebMatrix	B-Application
or	O
Visual	O
Studio	O
2012	O
and	O
later	O
.	O
</s>
<s>
(	O
In	O
Visual	O
Studio	O
2010	O
and	O
earlier	O
,	O
web	O
developers	O
developing	O
ASP.NET	B-Application
apps	O
used	O
ASP.NET	B-Application
Development	O
Server	O
,	O
codenamed	O
"	O
Cassini	O
"	O
.	O
)	O
</s>
<s>
FTP	B-Protocol
Publishing	O
Service	O
:	O
Lets	O
Web	O
content	O
creators	O
publish	O
content	O
securely	O
to	O
IIS	B-Application
7	I-Application
Web	B-Application
servers	I-Application
with	O
SSL-based	O
authentication	O
and	O
data	O
transfer	O
.	O
</s>
<s>
Administration	O
Pack	O
:	O
Adds	O
administration	O
UI	O
support	O
for	O
management	O
features	O
in	O
IIS	B-Application
7	I-Application
,	O
including	O
ASP.NET	B-Application
authorization	O
,	O
custom	O
errors	O
,	O
FastCGI	O
configuration	O
,	O
and	O
request	O
filtering	O
.	O
</s>
<s>
Application	B-Protocol
Request	I-Protocol
Routing	I-Protocol
:	O
Provides	O
a	O
proxy-based	O
routing	O
module	O
that	O
forwards	O
HTTP	B-Protocol
requests	I-Protocol
to	O
content	O
servers	O
based	O
on	O
HTTP	B-Protocol
headers	O
,	O
server	O
variables	O
,	O
and	O
load	O
balance	O
algorithms	O
.	O
</s>
<s>
URL	O
Rewrite	O
Module	O
:	O
Provides	O
a	O
rule-based	O
rewriting	O
mechanism	O
for	O
changing	O
request	O
URLs	O
before	O
they	O
are	O
processed	O
by	O
the	O
Web	B-Application
server	I-Application
.	O
</s>
<s>
WebDAV	B-Protocol
:	O
Lets	O
Web	O
authors	O
publish	O
content	O
securely	O
to	O
IIS	B-Application
7	I-Application
Web	B-Application
servers	I-Application
,	O
and	O
lets	O
Web	O
administrators	O
and	O
hosters	O
manage	O
WebDAV	B-Protocol
settings	O
using	O
IIS	B-Application
7	I-Application
management	O
and	O
configuration	O
tools	O
.	O
</s>
<s>
Web	O
Deployment	O
Tool	O
:	O
Synchronizes	O
IIS	O
6.0	O
and	O
IIS	B-Application
7	I-Application
servers	O
,	O
migrates	O
an	O
IIS	O
6.0	O
server	O
to	O
IIS	B-Application
7	I-Application
,	O
and	O
deploys	O
Web	O
applications	O
to	O
an	O
IIS	B-Application
7	I-Application
server	O
.	O
</s>
<s>
According	O
to	O
Netcraft	O
,	O
in	O
February	O
2014	O
,	O
IIS	O
had	O
a	O
"	O
market	O
share	O
of	O
all	O
sites	O
"	O
of	O
32.80	O
%	O
,	O
making	O
it	O
the	O
second	O
most	O
popular	O
web	B-Application
server	I-Application
in	O
the	O
world	O
,	O
behind	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
at	O
38.22	O
%	O
.	O
</s>
<s>
According	O
to	O
W3Techs	O
,	O
IIS	O
is	O
the	O
third	O
most	O
used	O
web	B-Application
server	I-Application
behind	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
(	O
1st	O
place	O
)	O
and	O
Nginx	B-Operating_System
.	O
</s>
<s>
Netcraft	O
data	O
in	O
February	O
2017	O
indicates	O
IIS	O
had	O
a	O
"	O
market	O
share	O
of	O
the	O
top	O
million	O
busiest	O
sites	O
"	O
of	O
10.19	O
%	O
,	O
making	O
it	O
the	O
third	O
most	O
popular	O
web	B-Application
server	I-Application
in	O
the	O
world	O
,	O
behind	O
Apache	B-Application
at	O
41.41	O
%	O
and	O
nginx	B-Operating_System
at	O
28.34	O
%	O
.	O
</s>
<s>
In	O
IIS	O
6.0	O
Microsoft	O
opted	O
to	O
change	O
the	O
behaviour	O
of	O
pre-installed	O
ISAPI	B-Library
handlers	O
,	O
many	O
of	O
which	O
were	O
culprits	O
in	O
the	O
vulnerabilities	O
of	O
4.0	O
and	O
5.0	O
,	O
thus	O
reducing	O
the	O
attack	O
surface	O
of	O
IIS	O
.	O
</s>
<s>
IIS	O
6.0	O
also	O
contained	O
a	O
new	O
kernel	O
HTTP	B-Protocol
stack	O
(	O
http.sys	O
)	O
with	O
a	O
stricter	O
HTTP	B-Protocol
request	O
parser	O
and	O
response	O
cache	O
for	O
both	O
static	O
and	O
dynamic	O
content	O
.	O
</s>
<s>
According	O
to	O
Secunia	O
,	O
,	O
IIS	B-Application
7	I-Application
had	O
a	O
total	O
of	O
six	O
resolved	O
vulnerabilities	O
while	O
IIS	O
6	O
had	O
a	O
total	O
of	O
eleven	O
vulnerabilities	O
,	O
out	O
of	O
which	O
one	O
was	O
still	O
unpatched	O
.	O
</s>
<s>
In	O
June	O
2007	O
,	O
a	O
Google	O
study	O
of	O
80	O
million	O
domains	O
concluded	O
that	O
while	O
the	O
IIS	O
market	O
share	O
was	O
23%	O
at	O
the	O
time	O
,	O
IIS	B-Application
servers	I-Application
hosted	O
49%	O
of	O
the	O
world	O
's	O
malware	O
,	O
the	O
same	O
as	O
Apache	B-Application
servers	I-Application
whose	O
market	O
share	O
was	O
66%	O
.	O
</s>
<s>
Possessing	O
one	O
of	O
the	O
long	O
term	O
asymmetric	O
secret	O
keys	O
used	O
to	O
establish	O
a	O
HTTPS	B-Protocol
session	O
should	O
not	O
make	O
it	O
easier	O
to	O
derive	O
the	O
short	O
term	O
session	O
key	O
to	O
then	O
decrypt	O
the	O
conversation	O
,	O
even	O
at	O
a	O
later	O
time	O
.	O
</s>
<s>
Diffie	B-Protocol
–	I-Protocol
Hellman	I-Protocol
key	I-Protocol
exchange	I-Protocol
(	O
DHE	O
)	O
and	O
elliptic	B-Protocol
curve	I-Protocol
Diffie	I-Protocol
–	I-Protocol
Hellman	I-Protocol
key	I-Protocol
exchange	I-Protocol
(	O
ECDHE	B-Protocol
)	O
are	O
in	O
2013	O
the	O
only	O
ones	O
known	O
to	O
have	O
that	O
property	O
.	O
</s>
