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ll
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it
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a
s
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k
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e
sts
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t
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tes
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n
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ies
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o
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tch
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tes
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ted
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e
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o
ry
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ti
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d
iffere
n
t
siz
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les
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o
m
p
a
re
d
K
ey
w
o
r
d
s
:
C
lo
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d
s
ec
u
r
ity
C
o
n
f
licts
r
eso
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tio
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C
o
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elatio
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Fire
wall
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u
les
R
ed
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n
d
an
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R
u
le
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eo
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d
er
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s
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c
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rticle
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CC B
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SA
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se
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A
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:
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Si
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g
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Ma
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o
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f
E
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g
in
ee
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in
g
a
n
d
T
e
ch
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o
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g
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jar
at
T
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h
n
o
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n
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s
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m
ed
ab
ad
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jar
at,
I
n
d
ia
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m
ail:
ass
o
_
p
s
m
aa
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@
g
tu
.
ed
u
.
in
1.
I
NT
RO
D
UCT
I
O
N
Sin
ce
f
ir
ewa
lls
ar
e
in
ten
d
ed
to
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id
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s
tile
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k
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co
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ter
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k
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d
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ield
web
s
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r
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s
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r
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g
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o
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r
e
n
t
n
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k
s
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wev
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e
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e
f
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o
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t
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cc
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r
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h
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lev
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s
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ity
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r
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d
b
y
f
i
r
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lls
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g
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ad
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ally
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ea
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ed
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r
t
h
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s
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n
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cr
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ti
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o
r
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h
f
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l
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les
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ad
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p
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f
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ix
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itio
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tatem
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ts
[
1
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th
at
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s
ed
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wh
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ata,
s
u
ch
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esti
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ess
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o
u
r
ce
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esti
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o
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ts
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to
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ls
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d
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s
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n
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ass
th
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o
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o
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ay
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s
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o
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n
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h
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ile
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n
d
r
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l
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its
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ter
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et
s
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r
f
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n
y
b
o
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y
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th
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p
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war
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o
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p
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ts
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n
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tr
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s
ac
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s
ar
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k
n
o
wn
as
n
e
t
wo
r
k
s
y
s
tem
s
,
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d
th
ey
in
clu
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m
ak
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g
a
p
p
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tm
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ts
,
s
en
d
in
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d
r
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ea
d
in
g
n
ews,
k
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d
is
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a
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p
u
r
ch
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lear
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in
g
[
2
]
.
I
n
ter
m
s
o
f
co
m
p
u
ter
s
,
n
etwo
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k
s
.
Secu
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is
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s
af
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u
ar
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en
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itiv
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ata
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er
s
a
n
d
th
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k
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wh
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[
3
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.
An
elec
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f
ir
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ll
is
n
etwo
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s
tem
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m
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k
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etwo
r
k
tr
af
f
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in
b
o
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n
d
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d
o
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t
b
o
u
n
d
,
in
co
m
p
lian
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with
in
clu
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g
u
id
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an
d
p
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o
to
co
ls
f
o
r
s
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r
ity
[
4
]
,
[
5
]
.
A
b
ar
r
ier
s
er
v
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as
th
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k
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n
o
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r
eliab
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[
6
]
.
I
d
en
tify
in
g
an
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m
alies
in
cl
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f
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in
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ar
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with
s
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p
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Ad
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eq
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p
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m
in
in
g
th
eir
m
alicio
u
s
n
e
s
s
.
T
h
is
en
tails
m
ax
im
is
in
g
s
e
cu
r
ity
ev
e
n
f
o
r
alter
ed
d
ata,
wh
ich
wo
u
ld
b
e
f
ar
m
o
r
e
c
h
allen
g
in
g
f
o
r
a
h
u
m
a
n
ex
p
er
t
to
f
in
d
.
Sin
ce
f
ir
ew
alls
ar
e
d
esig
n
ed
to
k
ee
p
h
o
s
tile
attac
k
s
o
u
t
o
f
co
m
p
u
ter
n
etwo
r
k
s
an
d
to
p
r
o
tect
web
s
ites
f
r
o
m
in
tr
u
s
i
o
n
,
th
ey
ar
e
a
n
ec
ess
ar
y
s
e
cu
r
ity
m
ea
s
u
r
e
f
o
r
co
n
n
ec
tin
g
t
o
co
n
tem
p
o
r
a
r
y
n
etwo
r
k
s
.
Ho
wev
er
,
in
th
e
e
v
en
t
th
at
th
e
r
u
les
p
r
o
v
id
e
d
d
o
n
o
t
c
o
v
er
e
v
er
y
n
etwo
r
k
ac
tiv
ity
,
th
e
f
i
r
ewa
ll
’
s
p
r
o
tectiv
e
m
ea
s
u
r
es
ar
e
g
r
ad
u
ally
r
ed
u
ce
d
.
T
h
u
s
,
p
u
ttin
g
s
tr
o
n
g
f
i
r
ewa
ll
r
u
les
in
to
p
lace
is
ess
en
tial
f
o
r
n
etwo
r
k
s
ec
u
r
ity
.
Six
c
o
n
d
itio
n
al
s
tatem
en
ts
m
ak
e
u
p
a
f
i
r
ewa
ll
r
u
le.
T
h
ese
s
tatem
en
ts
s
p
ec
if
y
wh
ich
d
ata
,
s
u
ch
as
th
e
I
P
ad
d
r
ess
es
o
f
th
e
s
o
u
r
ce
an
d
d
esti
n
atio
n
,
p
o
r
ts
,
p
r
o
t
o
co
ls
,
an
d
ac
tio
n
s
,
m
ay
an
d
ca
n
n
o
t m
o
v
e
(
B
lo
ck
ed
)
.
2.
L
I
T
E
R
AT
U
RE
R
E
VI
E
W
W
e
g
o
o
v
e
r
r
u
le
an
o
m
aly
c
h
e
ck
in
g
a
n
d
r
eso
l
u
tio
n
in
th
is
s
ec
tio
n
.
T
h
e
f
ir
s
t
s
tu
d
y
to
p
r
o
p
o
s
e
th
e
r
u
le
an
o
m
aly
m
o
d
el
f
o
r
f
ir
ewa
ll
r
u
les
with
a
co
r
r
esp
o
n
d
i
n
g
v
er
if
icatio
n
m
ec
h
an
is
m
was
i
n
[
7
]
.
I
n
th
is
,
it
is
d
ev
elo
p
e
d
th
e
r
u
le
an
o
m
al
y
with
in
a
s
in
g
le
f
ir
ewa
ll
as
well
as
b
etwe
en
f
ir
e
walls
in
2
0
0
3
af
ter
s
tu
d
y
in
g
th
e
in
ter
ac
tio
n
s
b
etwe
en
f
ir
ewa
ll
r
u
les
[
8
]
.
T
h
ese
r
esear
ch
er
s
s
u
g
g
ested
a
v
er
if
icatio
n
tech
n
iq
u
e
b
ased
o
n
th
e
s
tate
tr
an
s
it
d
iag
r
am
an
d
illu
s
tr
ated
a
p
o
licy
tr
ee
f
o
r
ea
ch
f
ir
ewa
ll
r
u
le.
I
n
[
7
]
,
it
is
d
ev
e
lo
p
ed
a
n
a
n
o
m
aly
ch
ec
k
in
g
tec
h
n
iq
u
e
an
d
m
o
d
e
lled
f
ir
ewa
ll
r
u
les
as
b
in
ar
y
d
ec
is
io
n
d
iag
r
am
s
(
B
DDs)
b
ased
o
n
th
eir
r
esear
c
h
.
A
co
n
v
en
tio
n
al
an
o
m
aly
r
e
s
o
lu
tio
n
s
y
s
tem
was
p
r
esen
ted
b
y
a
u
th
o
r
s
in
[
9
]
,
wh
o
s
e
k
ey
co
n
ce
p
t
is
co
n
cu
r
r
en
tly
m
ain
tain
in
g
in
p
u
t
an
d
o
u
tp
u
t
r
u
le
s
et.
T
h
e
p
r
e
s
en
ce
an
d
co
n
f
lu
e
n
ce
o
f
th
e
an
s
wer
wer
e
als
o
ex
am
in
ed
b
y
th
ese
s
ch
o
lar
s
.
Fire
wall
r
u
les
wer
e
s
u
g
g
ested
to
b
e
d
iv
id
ed
in
to
a
co
llectio
n
o
f
m
eta
-
r
u
les
b
y
au
th
o
r
in
[
1
0
]
,
wh
o
th
en
c
o
m
p
o
s
ed
th
ese
m
eta
-
r
u
les to
ac
co
m
p
lis
h
f
in
e
-
g
r
ain
r
u
le
a
d
m
in
is
tr
atio
n
.
Fu
r
th
e
r
m
o
r
e
,
co
m
p
ar
ab
le
r
ese
ar
ch
o
n
a
d
d
itio
n
al
s
af
ety
f
u
n
ctio
n
s
h
as
also
b
ee
n
n
o
ted
.
I
n
[
1
1
]
,
f
o
r
ex
am
p
le,
n
o
ted
th
at
an
I
Ps
ec
-
b
ased
VPN
h
a
d
t
h
e
s
am
e
is
s
u
es.
Fu
r
th
er
m
o
r
e,
in
[
1
2
]
ex
a
m
in
ed
th
e
co
n
f
lict
b
etwe
en
f
ir
ewa
lls
also
VPNs
(
also
k
n
o
wn
as
n
etwo
r
k
ad
d
r
ess
tr
an
s
lato
r
s
)
as
well
as
s
u
g
g
ested
a
m
atch
in
g
ch
ec
k
in
g
tech
n
iq
u
e.
Acc
o
r
d
i
n
g
to
th
eir
ea
r
lier
r
esear
ch
,
au
th
o
r
s
in
tr
o
d
u
ce
d
a
B
DD
-
b
ased
th
e
Op
e
n
Flo
w
p
r
o
to
co
l
f
lo
w
-
ta
b
le
ch
ec
k
in
g
ap
p
r
o
ac
h
[
1
3
]
with
t
h
e
ad
v
en
t
o
f
SDN.
T
h
is
m
eth
o
d
is
f
le
x
ib
le
en
o
u
g
h
to
b
e
u
s
ed
wit
h
a
s
in
g
le
th
e
Op
en
Flo
w
p
r
o
to
co
l
s
witch
.
Su
b
s
eq
u
en
tly
,
in
[
1
4
]
,
it
co
n
ce
n
tr
ate
d
o
n
th
e
Op
en
Flo
w
s
witch
’
s
an
o
m
aly
is
s
u
es
an
d
s
u
g
g
ested
e
m
p
lo
y
i
n
g
a
h
ier
ar
c
h
y
-
b
ased
f
lo
w
-
tab
le
(
HFT)
an
d
em
p
lo
y
in
g
a
tr
ee
s
tr
u
ctu
r
e
to
m
ak
e
ju
d
g
em
en
t
s
f
o
r
ev
er
y
in
d
iv
id
u
al
p
ac
k
et
.
Af
ter
a
y
ea
r
,
u
s
in
g
th
eir
p
r
ev
io
u
s
wo
r
k
,
SDN
co
n
tr
o
ller
API
was
d
ev
elo
p
e
d
b
y
th
ese
r
esear
ch
er
s
an
d
a
p
p
r
o
v
ed
f
o
r
u
s
ag
e
b
y
n
etwo
r
k
a
d
m
in
is
tr
ato
r
s
in
a
s
in
g
le
n
etwo
r
k
d
o
m
ai
n
[
1
5
]
.
I
n
o
r
d
e
r
to
a
d
d
r
ess
two
p
r
im
ar
y
is
s
u
es,
th
ese
r
esear
ch
er
s
p
r
o
p
o
s
ed
a
n
o
r
g
an
is
atio
n
al
s
h
ar
e
tr
ee
to
ca
teg
o
r
is
e
th
e
m
an
a
g
em
en
t
lev
e
l:
i
)
r
em
o
v
in
g
th
e
c
o
n
tr
o
l
p
lan
es
f
r
o
m
th
e
o
v
er
all
v
iew
o
f
th
e
n
etwo
r
k
,
an
d
ii
)
a
d
d
r
ess
in
g
co
n
f
licts
b
etwe
en
v
ar
io
u
s
u
s
er
s
.
I
n
r
esp
o
n
s
e
to
th
eir
wo
r
k
,
au
h
to
r
in
[
1
6
]
in
t
r
o
d
u
ce
d
an
in
ter
v
al
f
o
r
ests
m
o
d
el
f
o
r
ex
p
ed
itio
u
s
an
o
m
aly
test
in
g
an
d
p
r
iv
ileg
e
m
an
ag
em
en
t
u
tili
s
in
g
th
e
p
r
io
r
s
h
ar
in
g
tr
ee
.
I
n
a
s
ec
u
r
ity
f
u
n
ctio
n
al
ch
ain
,
th
er
e
is
n
’
t
cu
r
r
en
tly
a
m
eth
o
d
i
n
p
lace
to
r
eso
lv
e
an
o
m
alies p
er
tain
in
g
to
v
a
r
io
u
s
s
ec
u
r
ity
r
u
les.
T
h
er
ef
o
r
e,
we
s
u
g
g
est
a
n
o
v
e
l
tech
n
iq
u
e
to
a
d
d
r
ess
th
e
is
s
u
e
in
lig
h
t
o
f
th
e
r
esear
c
h
d
o
n
e
b
y
a
u
th
o
r
.
T
o
p
r
ev
en
t
tim
e
-
wastin
g
p
r
o
ce
s
s
es,
we
cr
ea
te
a
p
r
io
r
ity
-
b
ased
ap
p
r
o
ac
h
th
at
d
r
aws
i
n
s
p
ir
atio
n
f
r
o
m
th
e
d
esig
n
s
o
f
au
th
o
r
in
[
1
7
]
an
d
in
[
1
8
]
.
Ho
wev
er
,
in
s
tead
o
f
b
ein
g
em
p
lo
y
ed
f
o
r
S
DN
f
lo
w
tab
le
co
n
s
tr
u
ctio
n
,
o
u
r
s
u
g
g
ested
ap
p
r
o
ac
h
is
u
s
ed
f
o
r
ad
d
r
ess
in
g
an
o
m
alies p
er
tain
in
g
to
g
en
er
ic
s
ec
u
r
ity
r
u
l
es.
T
ab
le
1
ex
p
lain
s
m
em
o
r
y
u
tili
za
tio
n
o
f
f
ir
ewa
ll r
u
les.
T
ab
le
1
.
Me
m
o
r
y
u
tili
za
tio
n
b
y
d
if
f
er
e
n
t n
u
m
b
er
o
f
f
ir
ewa
ll
r
u
les
R
u
l
e
s
#
M
e
m
o
r
y
r
e
q
u
i
r
e
d
(
M
B
)
P
r
o
t
o
c
o
l
1
0
0
5
1
8
TC
P
2
0
0
9
5
6
TC
P
4
0
0
1
0
6
7
TC
P
6
0
0
2
0
1
5
TC
P
8
0
0
3
0
9
6
TC
P
1
0
0
0
6
0
6
2
TC
P
1
2
0
0
1
1
0
5
0
TC
P
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
I
SS
N:
2252
-
8
7
7
6
Memo
r
y
ma
n
a
g
eme
n
t o
f fir
ewa
ll filter
in
g
r
u
les u
s
in
g
mo
d
ified
tr
ee
r
u
le
a
p
p
r
o
a
c
h
(
Dh
w
a
n
i H
a
ka
n
i
)
143
A
f
ir
ewa
ll p
o
licy
’
s
s
tan
d
ar
d
f
o
r
m
at
f
o
r
p
ac
k
et
f
ilter
in
g
r
u
les
is
as f
o
llo
ws:
<o
r
d
er
><
p
r
o
to
c
o
l><
s
r
c_
ip
><
s
r
c_
p
o
r
t><
d
s
t_
ip
><
d
s
t_
p
o
r
t><
ac
tio
n
>
3.
I
DE
N
T
I
F
I
CA
T
I
O
N
O
F
AN
O
M
AL
I
E
S
3
.
1
.
Sh
a
do
wing
a
no
m
a
ly
T
h
e
s
h
ad
o
win
g
p
h
en
o
m
en
o
n
,
as
its
n
am
e
im
p
lies
,
o
cc
u
r
s
wh
en
a
p
ar
ticu
lar
r
u
le
tak
es
o
n
th
e
A
r
u
le
is
r
ef
er
r
ed
to
b
e
a
s
h
ad
o
w
r
u
le
o
f
a
p
r
ec
ed
in
g
r
u
le
wh
en
its
p
r
ed
icate
co
m
p
o
n
en
t m
atc
h
es th
e
p
r
em
is
e
elem
en
t
o
f
th
at
p
r
ev
io
u
s
r
u
le
b
u
t its
ac
t
io
n
s
ar
e
d
if
f
e
r
en
t
.
As in
F
ig
u
r
e
1
,
it sh
o
ws Sp
ac
e
f
o
r
r
eso
lu
t
io
n
o
f
a
n
o
m
alies.
(
∀
,
(
(
)
⊇
(
)
)
)
^
(
(
)
≠
(
)
)
Fig
u
r
e
1
.
Sp
ac
e
f
o
r
r
eso
lu
tio
n
o
f
an
o
m
alies
3
.
2
.
Co
rr
el
a
t
io
n
a
no
m
a
ly
T
wo
r
u
les
ar
e
s
aid
to
b
e
clo
s
e
ly
co
r
r
elate
d
wh
en
th
ey
h
av
e
d
if
f
er
en
t
ac
tio
n
f
ield
s
,
s
o
m
e
o
f
th
e
in
itial
r
u
le
’
s
p
r
e
d
icatio
n
f
ield
s
ar
e
t
h
e
s
am
e
as
o
r
s
m
aller
co
m
p
a
r
ed
to
th
e
r
elate
p
r
ed
ictio
n
f
i
eld
s
in
th
e
r
u
le
th
at
f
o
llo
ws,
an
d
th
e
r
em
ain
in
g
p
r
ed
icate
f
ield
s
in
th
e
s
u
b
s
eq
u
en
t
r
u
le
ar
e
a
s
u
p
er
s
et
o
f
th
e
p
r
ed
icate
f
ield
s
in
th
e
f
ir
s
t r
u
le.
3
.
3
.
G
ener
a
liza
t
io
n
a
no
m
a
ly
T
h
e
o
th
er
r
u
le
is
ca
lled
a
g
en
er
alis
atio
n
o
f
th
e
f
ir
s
t
r
u
le
wh
en
b
o
th
h
av
e
d
if
f
er
en
t
ac
tio
n
v
alu
es
b
u
t
ev
er
y
o
n
e
o
f
th
e
s
u
b
s
eq
u
e
n
t r
u
le
’
s
p
r
ed
icate
d
f
ield
s
m
atch
all
th
e
o
r
ig
in
al
r
u
le
’
s
p
r
e
d
icate
f
i
eld
s
.
(
∀
,
(
(
)
⊆
(
)
)
)
^
(
(
)
≠
(
)
)
I
t
is
n
o
t
th
e
s
am
e
as
o
b
s
er
v
in
g
,
d
esp
ite
th
e
s
im
ilar
ities
.
Un
lik
e
g
en
er
alis
atio
n
,
wh
ic
h
o
cc
u
r
s
wh
en
an
o
th
er
p
o
licy
ab
s
o
r
b
s
th
e
s
u
p
er
o
r
d
in
ate
p
o
licy
,
s
h
ad
o
win
g
o
cc
u
r
s
wh
en
th
e
p
r
ev
io
u
s
p
o
licy
m
atch
es
o
r
in
clu
d
es
a
s
u
b
o
r
d
in
ate
p
o
licy
.
T
h
e
g
e
n
er
alis
atio
n
an
o
m
aly
ar
is
es
wh
en
two
r
u
les
h
a
v
e
d
i
f
f
er
en
t
ac
tio
n
s
an
d
ev
er
y
p
ac
k
et
d
is
co
v
er
e
d
b
y
o
n
e
o
f
th
em
is
a
s
u
b
s
et
o
f
ev
er
y
p
ac
k
et
m
atch
b
y
th
e
o
th
er
.
3
.
4
.
Redund
a
ncy
a
no
m
a
l
y
E
lim
in
atin
g
a
r
ed
u
n
d
an
t
r
u
le
h
as
n
o
im
p
ac
t
o
n
a
s
ec
u
r
ity
p
o
licy
s
in
ce
it
ex
ec
u
tes
th
e
s
am
e
ac
tio
n
o
n
a
s
in
g
le
p
ac
k
et
as
an
o
t
h
er
r
u
le
.
R
eg
u
late
R
y
is
u
n
n
ec
ess
ar
y
i
n
id
en
tify
in
g
R
x
if
R
x
h
a
p
p
en
s
b
ef
o
r
e
R
y
with
in
th
e
s
eq
u
en
ce
,
R
y
is
a
p
a
r
t o
f
o
r
ex
ac
tly
th
e
s
am
e
as R
x
,
an
d
t
h
e
ac
tiv
ities
ar
e
eq
u
iv
alen
t.
∀
:
a
(
) ∩
b
(
)
≠
∅
ℎ
∈
{
,
,
,
,
,
}
a
(
) ∩
b
(
)
≠
∅
a
(
) ∩
b
(
)
≠
∅
a
(
) ∩
b
(
)
≠
∅
a
(
) ∩
b
(
)
≠
∅
ℎ
a
b
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
2
5
2
-
8
7
7
6
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
,
Vo
l.
1
4
,
No
.
1
,
A
p
r
il
20
2
5
:
141
-
1
5
2
144
4.
ANALY
SI
S A
ND
DE
T
E
CT
I
O
N
O
F
I
NT
RAF
I
RE
W
AL
L
ANO
M
AL
I
E
S
T
h
e
p
r
o
ce
s
s
o
f
class
if
y
in
g
p
a
ck
ets
in
v
o
lv
es
m
atch
in
g
ea
ch
o
n
e
in
tu
r
n
ag
ai
n
s
t
f
ir
ewa
ll
r
u
les
till
a
m
atch
is
o
b
tain
ed
.
T
h
e
h
ier
ar
ch
y
b
etwe
en
th
e
r
u
les
is
n
o
t
i
m
p
o
r
tan
t
i
f
th
ey
ar
e
s
elf
-
c
o
n
t
ain
ed
.
Fire
wall
r
u
les
f
r
eq
u
e
n
tly
h
av
e
o
n
e
f
ir
ewa
ll
r
u
le
co
n
n
ec
ted
to
an
o
th
er
ev
e
n
if
th
ey
m
ak
e
d
is
tin
ct
ch
o
ices.
I
n
th
is
in
s
tan
ce
,
co
n
f
licts
an
d
th
e
e
n
s
u
in
g
o
r
d
e
r
s
en
s
itiv
ity
h
av
e
lo
g
ically
i
n
ter
twin
ed
th
e
r
u
les with
in
a
f
ir
ewa
ll p
o
licy
.
T
h
u
s
,
th
e
ex
is
ten
ce
if
two
o
r
m
o
r
e
f
ilter
s
th
at
m
ay
m
atch
th
e
s
am
e
p
ac
k
et
o
r
th
e
ex
is
t
en
ce
o
f
a
n
ex
ce
p
tio
n
th
at
co
u
l
d
n
ev
er
m
atch
a
p
ac
k
et
th
at
cr
o
s
s
ed
th
e
f
ir
ewa
ll
is
cla
s
s
if
ied
a
s
an
in
tr
a
-
f
ir
ewa
ll
p
o
licy
an
o
m
aly
.
T
h
e
r
u
le
co
n
f
ig
u
r
at
io
n
an
o
m
aly
f
alls
in
to
o
n
e
o
f
th
r
ee
ca
te
g
o
r
ies,
as
d
e
f
in
ed
b
y
t
h
e
co
n
ce
p
t
o
f
p
o
licy
an
o
m
aly
: c
o
n
f
lict,
in
co
m
p
leten
ess
,
an
d
r
ed
u
n
d
a
n
cy
.
r
1
:F1
∈
[
0
,
7
]
∧
F2
∈
[
4
,
6
]
→ac
ce
p
t,
r
2
:F1
∈
[
0
,
8
]
∧
F2
∈
[
3
,
8
]
→d
is
ca
r
d
T
h
e
r
ea
s
o
n
wh
y
th
e
two
r
u
les,
r
1
an
d
r
2
,
a
r
e
at
o
d
d
s
is
th
at
c
er
tain
p
ac
k
ets
h
av
e
f
ield
s
t
h
at
f
u
lf
il
b
o
th
o
f
th
eir
p
r
e
d
icate
s
(
f
o
r
in
s
tan
ce
,
a
p
ac
k
et
with
F1
∈
[
0
,
7
]
∧
F2
∈
[
3
,
8
]
ca
n
s
atis
f
y
b
o
t
h
p
r
ed
icate
s
)
,
an
d
th
ese
two
r
u
les m
ak
e
d
if
f
er
e
n
t c
o
n
cl
u
s
io
n
s
.
C
o
n
s
eq
u
en
tly
,
it b
ec
o
m
es c
r
u
cial
to
co
n
s
id
er
h
o
w
th
ese
two
r
u
les r
elate
to
ea
ch
o
t
h
er
in
th
e
o
r
d
er
o
f
r
u
les.
I
t
’
s
p
r
o
b
ab
ly
a
co
n
s
is
ten
cy
m
is
tak
e
th
at
r
u
les
b
o
th
r
1
an
d
r
2
a
r
e
in
t
h
e
wr
o
n
g
s
eq
u
e
n
ce
.
5.
ANALY
SI
S A
ND
DE
T
E
CT
I
O
N
O
F
I
NT
E
RF
I
R
E
WA
L
L
ANO
M
A
L
I
E
S
Gen
er
ally
s
p
ea
k
in
g
,
if
a
n
y
two
f
ir
ewa
lls
o
n
a
co
n
n
ec
tio
n
f
i
lter
th
e
s
am
e
d
ata
d
if
f
er
en
tly
,
th
er
e
m
ay
b
e
an
in
ter
-
f
ir
ewa
ll
an
o
m
aly
.
W
e
ass
u
m
e
th
at
tr
af
f
ic
is
m
o
v
in
g
f
r
o
m
d
o
m
ai
n
s
D1
t
o
d
o
m
a
in
D2
,
as
s
h
o
wn
i
n
F
ig
u
r
e
2.
T
h
e
m
o
s
t
u
p
war
d
s
f
ir
ewa
ll
(
FW
1
)
is
th
e
o
n
e
th
at
is
clo
s
est
to
th
e
s
tr
ea
m
s
o
u
r
ce
d
o
m
ain
(
D1
)
,
an
d
th
e
m
o
s
t d
o
wn
f
ir
ewa
ll (
FW
n
)
is
th
e
o
n
e
th
at
is
clo
s
est to
th
e
f
lo
w
tar
g
et
d
o
m
ain
(
D
2
)
.
T
h
er
e
m
ay
b
e
an
o
m
alies
b
etwe
en
th
e
r
u
les
o
f
s
ev
er
al
f
ir
ewa
lls
ev
en
if
n
o
n
e
o
f
th
e
n
etwo
r
k
’
s
f
ir
ewa
ll
p
o
licies
i
n
clu
d
e
th
e
r
u
le
ab
n
o
r
m
alities
.
Fo
r
in
s
tan
ce
,
a
d
o
wn
s
tr
ea
m
f
ir
ewa
ll
m
ay
al
lo
w
tr
af
f
ic
th
at
a
n
u
p
s
tr
ea
m
f
ir
ewa
ll
is
b
lo
ck
in
g
,
o
r
v
ice
v
er
s
a.
Acc
o
r
d
in
g
to
[
1
9
]
,
an
an
o
m
aly
o
cc
u
r
s
f
o
r
an
y
tr
af
f
ic
g
o
in
g
f
r
o
m
d
o
m
ain
D1
to
d
o
m
ain
D2
i
f
a
n
y
o
f
th
e
f
o
llo
win
g
cir
c
u
m
s
tan
ce
s
is
tr
u
e,
u
tili
zin
g
th
e
n
etwo
r
k
m
o
d
el
d
ep
icte
d
in
Fig
u
r
e.
−
T
h
e
m
o
s
t
d
o
wn
s
tr
ea
m
f
ir
ewa
ll
ac
ce
p
ts
tr
af
f
ic
th
at
wa
s
p
r
ev
io
u
s
ly
r
ef
u
s
ed
th
r
o
u
g
h
an
y
o
f
th
e
s
u
b
s
eq
u
en
t
u
p
lan
d
f
ir
ewa
lls
;
−
T
h
e
m
o
s
t u
p
s
tr
ea
m
f
ir
ewa
ll a
llo
ws tr
af
f
ic
th
at
h
as b
ee
n
b
an
n
ed
b
y
al
l
o
f
th
e
f
o
llo
win
g
f
ir
e
walls;
an
d
−
T
h
e
d
o
wn
s
tr
ea
m
f
ir
ewa
ll
r
ej
ec
ts
tr
af
f
ic
th
at
was
p
r
ev
io
u
s
ly
d
en
ied
b
y
th
e
m
o
s
t
p
o
w
er
f
u
l
u
p
s
tr
ea
m
f
ir
ewa
ll.
An
y
tr
af
f
ic
th
at
is
p
er
m
itted
b
y
th
e
d
o
w
n
war
d
f
ir
ewa
ll
m
u
s
t
b
e
s
im
u
ltan
eo
u
s
ly
ad
m
itted
b
y
all
u
p
s
tr
ea
m
f
ir
ewa
lls
f
o
r
th
e
tr
af
f
ic
to
r
ea
c
h
its
d
esti
n
atio
n
.
Fig
u
r
e
2
.
I
n
ter
f
ir
ewa
ll a
n
o
m
a
lies
ex
am
p
le
with
d
o
m
ain
s
6.
L
I
M
I
T
AT
I
O
NS
I
n
tr
a
-
f
ir
ewa
ll
an
o
m
aly
d
etec
t
io
n
r
ef
er
s
to
id
e
n
tify
in
g
u
n
u
s
u
al
o
r
s
u
s
p
icio
u
s
ac
tiv
ities
with
in
a
f
ir
ewa
ll,
s
u
ch
as
d
e
v
iatio
n
s
f
r
o
m
ex
p
ec
ted
tr
af
f
ic
p
atter
n
s
o
r
v
io
latio
n
s
o
f
s
ec
u
r
ity
p
o
l
icies.
W
h
ile
it
is
a
cr
itical
co
m
p
o
n
e
n
t
o
f
n
etwo
r
k
s
ec
u
r
ity
,
th
is
ap
p
r
o
ac
h
h
as
s
e
v
er
al
lim
itatio
n
s
th
at
ca
n
r
ed
u
ce
its
ef
f
ec
tiv
en
ess
.
B
elo
w
ar
e
s
o
m
e
k
ey
lim
itatio
n
s
o
f
in
tr
a
-
f
ir
ewa
ll a
n
o
m
aly
d
etec
tio
n
:
1.
Hig
h
r
ate
o
f
f
alse p
o
s
itiv
es
E
x
p
lan
atio
n
:
An
o
m
aly
d
etec
ti
o
n
s
y
s
tem
s
ca
n
o
f
ten
f
lag
le
g
itima
te
tr
af
f
ic
as
s
u
s
p
icio
u
s
b
ec
au
s
e
th
ey
f
o
cu
s
o
n
d
e
v
iatio
n
s
f
r
o
m
n
o
r
m
al
p
atter
n
s
,
wh
ich
m
ig
h
t
i
n
clu
d
e
n
o
n
-
m
alicio
u
s
ch
an
g
es
(
e.
g
.
,
a
n
ew
s
er
v
ice
d
ep
lo
y
m
e
n
t
o
r
tem
p
o
r
ar
y
tr
af
f
ic
s
p
ik
es).
T
h
is
ca
n
o
v
e
r
wh
e
lm
s
ec
u
r
ity
team
s
with
aler
ts
,
lead
in
g
t
o
aler
t
f
atig
u
e
an
d
m
ak
in
g
it
d
if
f
ic
u
lt to
f
o
cu
s
o
n
ac
tu
al
th
r
ea
ts
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
I
SS
N:
2252
-
8
7
7
6
Memo
r
y
ma
n
a
g
eme
n
t o
f fir
ewa
ll filter
in
g
r
u
les u
s
in
g
mo
d
ified
tr
ee
r
u
le
a
p
p
r
o
a
c
h
(
Dh
w
a
n
i H
a
ka
n
i
)
145
I
m
p
ac
t:
Secu
r
ity
team
s
m
a
y
s
p
en
d
tim
e
ch
asin
g
d
o
w
n
b
e
n
ig
n
ev
e
n
ts
,
s
lo
win
g
d
o
wn
r
esp
o
n
s
e
to
r
ea
l
s
ec
u
r
ity
in
cid
en
ts
an
d
l
o
wer
in
g
o
v
er
all
o
p
er
atio
n
al
ef
f
icien
c
y
.
2.
Fals
e
n
eg
ativ
es a
n
d
m
is
s
ed
th
r
ea
ts
E
x
p
lan
atio
n
:
A
n
o
m
aly
d
e
tect
io
n
s
y
s
tem
s
ar
e
ty
p
ically
d
e
s
ig
n
ed
to
d
etec
t
u
n
k
n
o
wn
o
r
n
o
v
el
t
h
r
ea
ts
.
Ho
wev
er
,
s
o
p
h
is
ticated
attac
k
er
s
ca
n
d
is
g
u
is
e
th
eir
ac
ti
v
ities
to
ap
p
ea
r
as
n
o
r
m
al
tr
af
f
ic
(
e.
g
.
,
b
y
m
im
ick
in
g
r
eg
u
lar
u
s
er
b
e
h
av
io
r
o
r
u
s
in
g
e
n
cr
y
p
ted
co
m
m
u
n
icatio
n
)
.
T
h
is
ca
n
r
esu
lt
in
f
alse
n
eg
ativ
es,
wh
er
e
g
en
u
in
e
th
r
ea
ts
g
o
u
n
d
e
tecte
d
.
I
m
p
ac
t:
Miss
ed
an
o
m
alies
ca
n
lead
to
s
ec
u
r
ity
b
r
ea
ch
es,
wh
er
e
attac
k
er
s
ex
p
lo
it
v
u
l
n
e
r
ab
ilit
ies
with
o
u
t
tr
ig
g
er
in
g
an
y
aler
ts
.
3.
L
im
ited
v
is
ib
ilit
y
in
to
en
cr
y
p
t
ed
tr
af
f
ic
E
x
p
lan
atio
n
:
A
g
r
o
win
g
am
o
u
n
t
o
f
n
etwo
r
k
tr
af
f
ic
is
en
cr
y
p
ted
,
m
ak
in
g
it
d
if
f
ic
u
lt
f
o
r
tr
ad
itio
n
al
f
ir
ewa
lls
an
d
an
o
m
aly
d
etec
ti
o
n
s
y
s
tem
s
to
i
n
s
p
ec
t
th
e
co
n
t
en
ts
o
f
p
ac
k
ets.
W
ith
o
u
t
th
e
a
b
ilit
y
to
d
ec
r
y
p
t
tr
af
f
ic,
th
ese
s
y
s
tem
s
ca
n
o
n
ly
r
ely
o
n
m
etad
ata
s
u
ch
as
p
ac
k
et
s
ize
o
r
tr
af
f
ic
p
atter
n
s
,
wh
ich
m
ay
n
o
t
b
e
s
u
f
f
icien
t to
d
etec
t a
n
o
m
alies.
I
m
p
ac
t:
An
o
m
alies
in
en
cr
y
p
ted
tr
af
f
ic
m
ay
b
e
m
is
s
ed
,
r
ed
u
cin
g
th
e
ef
f
ec
tiv
e
n
ess
o
f
in
tr
a
-
f
ir
ewa
ll
d
etec
tio
n
in
id
e
n
tify
in
g
m
o
d
e
r
n
attac
k
s
th
at
u
s
e
en
cr
y
p
tio
n
t
o
ev
ad
e
d
etec
tio
n
.
4.
Dif
f
icu
lty
in
d
ef
i
n
in
g
“
n
o
r
m
al
”
b
eh
av
io
r
E
x
p
lan
atio
n
:
E
s
tab
lis
h
in
g
a
b
aselin
e
f
o
r
wh
at
is
co
n
s
id
er
ed
“
n
o
r
m
al
”
b
e
h
av
io
r
i
n
a
n
etwo
r
k
is
ch
allen
g
in
g
,
esp
ec
ially
in
d
y
n
am
ic
en
v
ir
o
n
m
e
n
ts
wh
er
e
tr
af
f
ic
p
atter
n
s
,
ap
p
licatio
n
s
,
an
d
s
er
v
ices
ch
an
g
e
f
r
eq
u
e
n
tly
.
Fire
walls
o
f
ten
l
a
ck
th
e
co
n
tex
t
n
ee
d
e
d
to
ac
cu
r
ately
d
ef
in
e
wh
at
is
n
o
r
m
al,
lead
in
g
to
in
ef
f
ec
tiv
e
d
etec
tio
n
.
I
m
p
ac
t:
Sy
s
tem
s
m
ay
eith
er
b
ec
o
m
e
to
o
s
en
s
itiv
e
(
lead
in
g
to
f
alse
p
o
s
itiv
es)
o
r
to
o
len
ien
t
(
lead
in
g
to
f
alse n
eg
ativ
es)
if
th
e
b
aselin
e
is
n
o
t w
ell
-
d
ef
in
ed
.
5.
L
ac
k
o
f
c
o
n
tex
tu
al
awa
r
e
n
ess
E
x
p
lan
atio
n
:
T
r
ad
itio
n
al
f
ir
e
walls
f
o
cu
s
p
r
im
ar
ily
o
n
p
a
ck
et
-
lev
el
in
f
o
r
m
atio
n
,
s
u
ch
as
s
o
u
r
ce
an
d
d
esti
n
atio
n
I
P
ad
d
r
ess
es,
p
o
r
ts
,
an
d
p
r
o
to
c
o
ls
.
T
h
is
lim
ited
v
iew
o
f
ten
lack
s
th
e
b
r
o
a
d
er
co
n
tex
t,
s
u
ch
as
u
s
er
b
eh
av
i
o
r
,
a
p
p
licatio
n
-
lev
el
d
ata,
o
r
n
etwo
r
k
-
wid
e
tr
af
f
ic
p
atter
n
s
,
wh
ich
a
r
e
cr
u
cial
f
o
r
ac
c
u
r
ately
d
etec
tin
g
an
o
m
alies.
I
m
p
ac
t:
Fire
walls
m
ay
s
tr
u
g
g
le
to
d
etec
t
m
o
r
e
s
o
p
h
is
ticated
attac
k
s
th
at
b
len
d
in
wit
h
n
o
r
m
al
tr
af
f
ic
p
atter
n
s
,
esp
ec
ially
th
o
s
e
o
p
e
r
atin
g
at
h
ig
h
e
r
lev
els
o
f
th
e
n
e
two
r
k
s
tack
(
e.
g
.
,
ap
p
licatio
n
o
r
u
s
er
lev
el)
.
6.
Dif
f
icu
lty
in
h
a
n
d
lin
g
lar
g
e
an
d
co
m
p
le
x
n
etwo
r
k
s
E
x
p
lan
atio
n
:
I
n
lar
g
e
o
r
d
is
tr
ib
u
ted
n
etwo
r
k
s
,
s
u
c
h
as
in
m
u
lti
-
clo
u
d
o
r
h
y
b
r
id
en
v
i
r
o
n
m
en
ts
,
tr
a
f
f
ic
p
atter
n
s
ca
n
b
e
h
ig
h
l
y
co
m
p
le
x
.
Fire
walls
in
s
u
ch
en
v
ir
o
n
m
en
ts
m
u
s
t
p
r
o
ce
s
s
v
ast
am
o
u
n
t
s
o
f
d
ata,
wh
ich
in
cr
ea
s
es
th
e
d
if
f
icu
lty
o
f
d
et
ec
tin
g
s
u
b
tle
an
o
m
alies.
Netwo
r
k
ch
an
g
es,
s
u
ch
as
s
ca
lin
g
o
f
s
er
v
ices
o
r
in
tr
o
d
u
ctio
n
o
f
n
ew
d
e
v
ices,
ca
n
f
u
r
t
h
er
co
m
p
licate
an
o
m
al
y
d
etec
tio
n
.
I
m
p
ac
t:
T
h
e
co
m
p
lex
ity
a
n
d
v
o
lu
m
e
o
f
d
ata
ca
n
lead
to
s
lo
wer
d
etec
tio
n
o
r
m
is
s
ed
an
o
m
alies,
esp
ec
ially
wh
en
tr
af
f
ic
s
p
a
n
s
m
u
ltip
le
in
t
er
co
n
n
ec
ted
en
v
ir
o
n
m
e
n
ts
.
7.
L
im
ited
au
to
m
atio
n
an
d
r
esp
o
n
s
e
ca
p
ab
ilit
ies
E
x
p
lan
atio
n
:
Ma
n
y
i
n
tr
a
-
f
ir
ewa
ll
an
o
m
aly
d
etec
tio
n
s
y
s
tem
s
g
en
er
ate
aler
ts
b
u
t
r
eq
u
ir
e
m
a
n
u
al
in
ter
v
en
tio
n
to
a
d
d
r
ess
p
o
te
n
t
ial
th
r
ea
ts
.
As
cy
b
er
attac
k
s
b
e
co
m
e
m
o
r
e
s
o
p
h
is
ticated
an
d
r
ap
id
,
t
h
e
n
ee
d
f
o
r
im
m
e
d
iate
r
esp
o
n
s
e
b
ec
o
m
es m
o
r
e
cr
itical.
I
m
p
ac
t:
Dela
y
s
in
m
an
u
al
r
e
s
p
o
n
s
e
to
d
etec
ted
an
o
m
alies
ca
n
lead
to
s
ec
u
r
ity
b
r
ea
ch
es.
Au
to
m
atio
n
ca
p
ab
ilit
ies f
o
r
an
o
m
aly
d
etec
tio
n
ar
e
o
f
ten
lim
ited
,
r
e
d
u
cin
g
th
e
ab
ilit
y
to
r
esp
o
n
d
to
th
r
e
ats in
r
ea
l
-
tim
e.
7.
RE
SU
L
T
S AN
D
D
I
SCU
SS
I
O
N
T
h
e
s
ec
tio
n
lo
o
k
s
at
im
p
lem
e
n
tatio
n
s
p
ec
if
ics
an
d
t
h
e
ef
f
e
ctiv
en
ess
o
f
th
e
s
u
g
g
ested
f
ir
ewa
ll
r
u
le
an
o
m
aly
d
etec
tio
n
.
On
e
h
o
s
t
an
d
v
i
r
tu
al
m
ac
h
i
n
es
ar
e
cr
ea
ted
an
d
m
an
a
g
ed
u
s
in
g
clo
u
d
s
im
,
a
clo
u
d
s
im
u
lato
r
,
an
d
it
is
d
ev
elo
p
ed
u
s
in
g
th
e
J
av
a
p
latf
o
r
m
.
T
h
e
s
y
s
tem
s
p
ec
s
in
clu
d
e
an
I
n
tel
Pen
tiu
m
2
.
3
0
GHz
C
PU,
4
GB
o
f
R
AM
,
an
d
W
in
d
o
ws 1
0
6
4
-
b
it.
T
h
is
p
ap
er
s
u
g
g
ests
an
an
o
m
aly
r
eso
lu
tio
n
m
eth
o
d
b
ased
o
n
f
ir
ewa
ll
tr
ee
s
.
T
h
e
f
o
llo
wi
n
g
ar
e
th
e
cr
u
cial
s
tep
s
:
W
h
en
c
r
ea
tin
g
a
tr
ee
,
a
p
o
licy
is
co
n
v
er
ted
in
t
o
a
co
r
r
esp
o
n
d
in
g
f
ir
ewa
ll
tr
e
e
b
y
u
s
e
o
f
a
s
im
ilar
f
ir
ewa
ll
tr
ee
cr
ea
tio
n
tech
n
iq
u
e,
an
d
th
e
r
u
le
s
ec
tio
n
s
t
h
at
o
v
er
lap
ar
e
n
o
ted
.
A
p
at
h
with
in
a
s
u
b
tr
ee
is
estab
lis
h
ed
u
s
in
g
th
e
co
r
r
esp
o
n
d
in
g
tr
ee
.
T
h
e
s
u
b
tr
ee
p
ath
is
u
s
ed
t
o
id
e
n
tify
th
e
a
p
p
r
o
p
r
ia
te
an
o
m
alo
u
s
r
u
les
[
2
0
]
,
[
21]
.
Fig
u
r
e
3
d
e
p
icts
p
r
o
p
o
s
ed
ar
ch
itectu
r
e
o
f
o
u
r
tr
e
e
r
u
le
f
ir
ewa
ll
ap
p
r
o
ac
h
.
Fig
u
r
e
4
s
h
o
ws
r
u
n
n
in
g
co
d
e
in
n
etb
ea
n
s
.
W
h
en
a
tr
af
f
ic
p
ac
k
et
s
atis
f
ie
s
ce
r
tain
r
eq
u
ir
em
en
ts
,
th
e
ad
m
in
is
tr
ato
r
ca
n
id
en
tify
it.
W
h
ich
p
o
licy
d
ec
id
es
wh
eth
er
to
ac
ce
p
t
o
r
r
ejec
t
d
ata
p
ac
k
ets
will
b
e
m
ad
e
clea
r
in
th
e
r
ep
o
r
t.
W
h
en
a
n
ew
r
u
le
is
cr
ea
ted
,
th
e
ad
m
in
is
tr
ato
r
m
ay
ch
e
ck
t
o
s
ee
if
it
d
if
f
e
r
s
f
r
o
m
th
e
p
r
e
v
io
u
s
ly
estab
lis
h
ed
p
o
lic
y
b
y
co
m
p
ar
in
g
it
to
th
e
r
elate
d
tr
ee
[
2
2
]
.
Evaluation Warning : The document was created with Spire.PDF for Python.
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2
5
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8
7
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I
n
t J I
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&
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m
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,
Vo
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1
4
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1
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A
p
r
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20
2
5
:
141
-
1
5
2
146
W
e
p
u
t
th
e
s
u
g
g
ested
m
eth
o
d
s
an
d
s
tr
ateg
ies
in
to
p
r
ac
t
ice
in
a
s
o
f
twar
e
to
o
l
p
r
o
t
o
ty
p
e.
T
h
is
p
r
o
to
ty
p
e
co
n
s
is
ts
o
f
two
m
o
d
u
les
an
d
was
cr
ea
ted
in
J
av
a
f
o
r
p
o
r
tab
ilit
y
.
T
h
e
c
o
n
f
ig
u
r
ati
o
n
o
f
t
h
e
in
teg
r
ate
d
f
ir
ewa
lls
an
d
a
d
escr
ip
tio
n
o
f
th
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s
ef
u
ln
ess
an
d
in
teg
r
ity
o
f
d
ata.
9.
F
I
RE
W
AL
L
RU
L
E
S P
O
L
I
CY
E
DI
T
I
NG
Netwo
r
k
ad
m
in
is
tr
ato
r
s
f
r
eq
u
en
tly
wr
ite
f
ir
ewa
ll
p
o
licies,
wh
ich
ar
e
th
en
p
er
io
d
icall
y
m
o
d
i
f
ied
(
b
y
ad
d
in
g
,
c
h
an
g
in
g
,
o
r
d
el
etin
g
r
u
les)
to
tak
e
n
ew
s
ec
u
r
ity
n
ee
d
s
an
d
n
etwo
r
k
s
tr
u
ctu
r
e
ch
an
g
es
in
to
ac
co
u
n
t.
I
t
ca
n
b
e
s
ig
n
if
ica
n
tly
m
o
r
e
d
if
f
ic
u
lt
to
ed
it
a
co
r
p
o
r
ate
s
ec
u
r
ity
p
o
licy
th
a
n
to
cr
ea
te
a
n
ew
o
n
e.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
2
5
2
-
8
7
7
6
I
n
t J I
n
f
&
C
o
m
m
u
n
T
ec
h
n
o
l
,
Vo
l.
1
4
,
No
.
1
,
A
p
r
il
20
2
5
:
141
-
1
5
2
150
Sin
ce
a
n
ew
s
cr
ee
n
in
g
r
u
le
m
i
g
h
t
n
o
t
b
e
ap
p
licab
le
to
all
n
e
two
r
k
s
u
b
-
d
o
m
ain
s
,
it
is
im
p
o
r
tan
t
to
en
s
u
r
e
t
h
at
it
is
ap
p
r
o
p
r
iately
p
lace
d
in
th
e
ap
p
r
o
p
r
iate
f
ir
ewa
lls
to
p
r
ev
en
t
allo
win
g
o
r
b
lo
ck
in
g
u
n
wa
n
ted
tr
a
f
f
ic.
Fu
r
th
er
m
o
r
e
,
b
ec
au
s
e
a
lo
ca
l
f
ir
ewa
ll
p
o
licy
’
s
r
u
les
ar
e
a
r
r
an
g
e
d
in
a
ce
r
tain
o
r
d
er
,
a
d
d
in
g
a
n
ew
r
u
l
e
r
eq
u
ir
es c
ar
ef
u
l c
o
n
s
id
er
atio
n
to
p
r
ev
e
n
t in
tr
a
-
f
ir
ewa
ll a
n
o
m
alies.
T
h
e
s
am
e
h
o
ld
s
tr
u
e
if
th
e
r
e
g
u
latio
n
is
ch
an
g
e
d
o
r
elim
in
ated
.
T
h
is
s
ec
tio
n
co
v
er
s
f
ir
e
wall
p
o
licy
ed
itin
g
m
eth
o
d
s
th
at
p
r
e
v
en
t
an
o
m
alies
f
r
o
m
b
ein
g
in
tr
o
d
u
ce
d
b
y
p
o
licy
c
h
an
g
es
a
n
d
g
r
ea
tly
s
im
p
lify
r
u
le
ed
itin
g
wo
r
k
.
I
n
o
r
d
er
to
p
r
e
v
en
t
in
tr
a
-
an
d
i
n
ter
-
f
ir
ewa
ll
an
o
m
alies,
th
e
p
o
licy
ed
ito
r
ass
is
ts
th
e
u
s
er
in
id
en
tify
in
g
th
e
a
p
p
r
o
p
r
iate
f
ir
ewa
lls
to
p
lace
n
ew
r
u
les
with
in
an
d
in
l
o
ca
tin
g
th
em
t
h
er
e.
I
t
also
o
f
f
er
s
v
is
u
al
aid
s
to
h
elp
u
s
er
s
m
o
n
ito
r
a
n
d
v
alid
ate
p
o
licy
c
h
an
g
es.
A
d
m
in
is
tr
ato
r
s
m
ay
ad
d
,
ch
an
g
e,
an
d
d
elete
r
u
les
f
r
o
m
th
e
f
ir
ewa
ll p
o
licy
with
o
u
t a
n
y
p
r
io
r
e
x
p
er
tis
e
o
r
u
n
d
e
r
s
tan
d
in
g
b
y
u
s
in
g
th
e
p
o
licy
e
d
ito
r
.
−
R
u
le
i
n
s
er
tio
n
T
h
er
e
ar
e
two
p
h
ases
in
v
o
lv
e
d
in
ad
d
in
g
a
n
ew
r
eg
u
latio
n
t
o
th
e
g
lo
b
al
s
ec
u
r
ity
p
o
licy
.
F
in
d
in
g
th
e
f
ir
ewa
lls
wh
er
e
th
e
r
u
le
s
h
o
u
l
d
b
e
in
s
talled
is
th
e
f
ir
s
t
s
tep
.
T
h
is
is
n
ec
ess
ar
y
to
en
s
u
r
e
th
at
th
e
f
ilter
in
g
r
u
le
is
o
n
ly
a
p
p
lied
t
o
th
e
p
er
tin
e
n
t
s
u
b
-
d
o
m
ain
s
an
d
th
at
n
o
ab
n
o
r
m
alities
ar
is
e
b
etwe
en
th
e
f
i
r
ewa
lls
.
I
d
en
tify
in
g
th
e
co
r
r
ec
t
s
eq
u
en
ce
f
o
r
th
e
n
ewly
im
p
lem
en
ted
r
u
le
in
ea
ch
o
f
th
ese
f
ir
ewa
lls
is
t
h
e
s
ec
o
n
d
s
tag
e
i
n
p
r
ev
en
tin
g
th
e
cr
ea
tio
n
o
f
in
tr
a
-
f
ir
ewa
ll a
n
o
m
alies.
Gen
er
ally
s
p
ea
k
in
g
,
an
y
r
u
le
t
h
at
m
atch
es
a
s
u
p
er
s
et
s
h
o
u
ld
co
m
e
b
ef
o
r
e
th
is
r
u
le,
an
d
an
y
r
u
le
th
at
m
atch
es
th
is
r
u
le
’
s
s
u
b
s
et
s
h
o
u
ld
co
m
e
af
ter
it.
T
h
e
r
e
g
io
n
a
l
p
o
licy
tr
ee
is
em
p
lo
y
ed
to
id
en
tify
an
y
p
o
s
s
ib
le
an
o
m
alies
an
d
m
ain
tain
tr
ac
k
o
f
th
e
n
ew
r
u
le
’
s
p
r
o
p
er
o
r
d
e
r
in
g
.
B
y
co
m
p
ar
in
g
ea
ch
f
ield
o
f
th
e
n
ew
r
u
le
to
th
e
r
elev
an
t
tr
ee
b
r
an
ch
v
alu
e
s
,
we
f
ir
s
t
lo
o
k
f
o
r
th
e
p
r
o
p
er
r
u
le
lo
ca
tio
n
in
th
e
p
o
licy
tr
e
e.
T
h
e
s
eq
u
en
ce
o
f
v
alu
es
o
f
th
e
r
u
le
th
at
h
a
s
b
ee
n
ad
d
ed
th
u
s
f
ar
is
less
th
an
th
e
b
ar
e
m
in
im
u
m
n
u
m
b
er
f
o
r
a
ll
th
e
r
eg
u
latio
n
s
i
n
th
at
b
r
an
ch
if
th
e
f
iel
d
r
esu
lt is
a
p
o
r
tio
n
o
f
th
e
b
r
a
n
ch
.
T
h
e
o
r
d
er
o
f
th
e
m
o
s
t
r
ec
en
t
r
u
le
th
u
s
f
ar
is
h
ig
h
er
th
an
th
e
h
ig
h
est
o
r
d
er
f
o
r
ea
ch
o
f
th
e
r
u
les
th
at
ex
is
t
i
n
th
is
b
r
an
ch
o
f
r
u
les
if
th
e
f
ield
r
esu
lt
is
a
c
o
m
b
in
ati
o
n
o
f
t
h
e
b
r
an
c
h
.
C
o
n
v
er
s
ely
,
in
t
h
e
e
v
en
t
t
h
at
a
r
u
le
is
d
is
co
n
tin
u
o
u
s
,
it
ca
n
g
r
an
t
an
y
o
r
d
er
in
s
id
e
th
e
p
o
licy
.
Similar
to
th
is
,
s
o
lo
n
g
as
th
e
f
ield
’
s
v
alu
e
m
atch
es
th
e
b
r
an
ch
ex
ac
tly
o
r
m
atch
es
a
p
o
r
tio
n
o
f
it,
th
e
tr
ee
b
r
o
wsi
n
g
p
r
o
ce
s
s
k
ee
p
s
ass
e
s
s
in
g
th
e
s
u
b
s
eq
u
en
t
f
ield
s
in
a
r
u
le
r
ec
u
r
s
iv
ely
.
T
h
e
r
u
le
is
en
ter
ed
an
d
g
iv
e
n
th
e
o
r
d
er
d
ec
i
d
e
d
u
p
o
n
d
u
r
i
n
g
th
e
b
r
o
wsi
n
g
p
h
ase
wh
e
n
it
r
ea
ch
es
th
e
ac
tio
n
f
ield
.
E
v
er
y
tim
e
a
d
is
ju
n
ct
o
r
s
u
p
e
r
s
et
m
atch
i
n
g
is
d
is
co
v
er
ed
,
a
n
ew
b
r
an
ch
is
m
ad
e
f
o
r
th
e
n
e
w
r
u
le.
T
h
e
p
o
licy
wr
iter
r
ejec
ts
th
e
n
ew
r
u
le
an
d
in
f
o
r
m
s
th
e
in
d
iv
id
u
al
with
a
s
u
itab
le
n
o
tific
atio
n
if
it
is
d
u
p
licate
b
ec
au
s
e
it
is
a
p
r
ec
is
e
m
atch
o
r
a
p
o
r
tio
n
o
f
th
e
m
at
ch
an
d
p
er
f
o
r
m
s
th
e
s
am
e
ac
tio
n
as a
n
ex
is
tin
g
r
u
le.
−
R
u
le
r
em
o
v
al
An
in
ter
-
f
ir
ewa
ll
an
o
m
al
y
m
a
y
b
e
cr
ea
ted
in
d
is
tr
ib
u
ted
f
ir
e
wall
s
etu
p
s
wh
en
a
r
u
le
is
r
em
o
v
ed
f
r
o
m
a
p
ar
ticu
lar
f
ir
ewa
ll.
Fo
r
i
n
s
tan
ce
,
r
e
m
o
v
in
g
a
“
d
e
n
y
”
r
u
le
with
in
a
n
u
p
s
tr
ea
m
f
ir
ewa
ll
will
ca
u
s
e
s
p
u
r
io
u
s
tr
af
f
ic
to
f
l
o
w
d
o
w
n
s
tr
ea
m
;
h
o
wev
er
,
r
e
m
o
v
i
n
g
a
“
ac
ce
p
t
”
r
u
le
will
b
lo
ck
th
e
ap
p
r
o
p
r
iate
tr
af
f
ic
an
d
ca
u
s
e
all
d
o
wn
s
tr
ea
m
r
u
les th
at
ar
e
r
ela
ted
(
ex
ac
t,
s
u
b
s
et,
o
r
s
u
p
er
s
et)
to
b
e
s
h
ad
o
wed
.
T
o
f
in
d
th
e
n
etwo
r
k
p
ath
b
et
wee
n
ea
ch
s
o
u
r
ce
-
d
esti
n
atio
n
d
o
m
ain
p
air
t
h
at
is
im
p
o
r
tan
t
to
th
is
r
u
le,
we
em
p
lo
y
th
e
s
am
e
m
eth
o
d
th
at
was
d
etailed
in
th
e
r
u
le
in
s
er
tio
n
p
r
o
ce
d
u
r
e.
T
h
e
r
u
le
is
d
elete
d
f
r
o
m
th
e
f
ir
ewa
ll
’
s
p
o
licy
in
th
e
f
o
llo
win
g
m
an
n
e
r
in
t
h
e
s
ec
o
n
d
p
h
ase.
W
e
d
elete
th
e
r
u
le
f
r
o
m
th
e
f
ir
ewa
lls
in
all
p
ath
way
s
f
r
o
m
s
o
u
r
ce
to
d
es
tin
atio
n
if
it
is
a
“
ac
ce
p
t
”
r
u
le.
I
f
th
e
r
u
le
is
d
elete
d
f
r
o
m
th
e
u
p
s
tr
ea
m
o
r
d
o
wn
s
tr
ea
m
f
ir
ewa
lls
,
r
esp
ec
tiv
ely
,
s
h
ad
o
win
g
o
r
s
p
u
r
io
u
s
n
ess
an
o
m
aly
will
r
esu
lt.
On
th
e
o
th
er
h
a
n
d
,
s
in
c
e
a
“
d
en
y
”
r
u
le
h
as
n
o
im
p
ac
t
a
cr
o
s
s
o
th
er
f
ir
ewa
ll
in
th
e
n
et
wo
r
k
,
we
s
im
p
ly
r
em
o
v
e
th
e
r
u
le
f
r
o
m
th
e
cu
r
r
en
t
f
ir
ewa
ll in
th
is
ca
s
e.
An
o
th
er
cr
u
cial
ac
tio
n
in
th
e
f
ir
ewa
ll
p
o
licy
is
m
o
d
if
y
in
g
a
r
u
le.
No
n
eth
eless
,
u
s
in
g
th
e
m
eth
o
d
s
f
o
r
r
u
le
d
eletio
n
a
n
d
in
s
er
tio
n
co
v
er
ed
in
th
is
s
ec
tio
n
,
a
c
h
an
g
e
d
r
u
le
m
ay
b
e
s
im
p
ly
c
h
ec
k
ed
a
n
d
ad
d
ed
.
10.
P
SE
UDO
CO
D
E
I
N
D
E
T
AI
L
T
h
is
s
tu
d
y
p
r
o
p
o
s
es
a
f
ir
ewa
ll
tr
ee
-
b
ased
an
o
m
aly
d
etec
tio
n
m
eth
o
d
.
T
h
e
c
r
u
cial
ac
tio
n
s
ar
e
as
f
o
llo
ws:
Usi
n
g
a
m
atch
i
n
g
f
ir
ewa
ll
tr
ee
p
r
o
d
u
ctio
n
ap
p
r
o
ac
h
,
t
h
e
p
o
licy
is
tr
a
n
s
f
o
r
m
e
d
in
t
o
an
an
alo
g
o
u
s
f
ir
ewa
ll
tr
ee
,
an
d
th
e
o
v
e
r
lap
p
in
g
p
ar
ts
o
f
th
e
r
eg
u
latio
n
s
ar
e
s
av
ed
d
u
r
in
g
th
e
tr
ee
cr
e
atio
n
p
r
o
ce
s
s
.
T
h
e
co
r
r
esp
o
n
d
in
g
tr
ee
is
u
s
ed
to
g
en
er
ate
a
p
ath
in
s
id
e
a
s
u
b
tr
ee
.
T
h
e
co
r
r
esp
o
n
d
in
g
an
o
m
al
o
u
s
r
u
les
ar
e
f
o
u
n
d
b
ased
u
p
o
n
th
e
s
u
b
t
r
ee
p
ath
.
T
r
af
f
ic
p
ac
k
ets
th
at
m
ee
t
s
ev
e
r
al
r
u
les
ca
n
b
e
id
en
tifie
d
b
y
t
h
e
ad
m
i
n
is
tr
ato
r
.
T
h
e
r
e
p
o
r
t
will
s
p
ec
if
y
wh
ich
p
o
lic
y
d
eter
m
in
es
wh
et
h
er
th
e
d
ata
p
ac
k
et
a
r
e
allo
we
d
o
r
r
ef
u
s
ed
.
T
h
e
a
d
m
in
is
tr
ato
r
h
as
th
e
ab
ilit
y
t
o
co
m
p
ar
e
a
n
ewly
in
tr
o
d
u
ce
d
r
u
le
to
th
e
m
atch
in
g
tr
ee
an
d
d
e
ter
m
in
e
wh
eth
er
it
d
ev
iate
s
f
r
o
m
th
e
o
r
ig
in
al
p
o
licy
.
T
h
e
f
ir
ewa
ll
r
u
les
ar
e
r
ep
r
esen
ted
b
y
th
e
tr
ee
m
o
d
el
,
wh
ich
ca
n
a
d
d
itio
n
ally
b
e
u
s
ed
to
s
wif
tly
s
p
o
t
ir
r
eg
u
lar
ities
in
th
e
r
u
les
an
d
r
elatio
n
s
h
ip
s
.
T
h
e
co
n
d
itio
n
al
elem
en
t
is
s
h
o
wn
b
y
th
e
n
o
d
e.
E
ac
h
lev
el
o
f
th
e
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