<s>
A	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
is	O
a	O
standalone	O
device	O
that	O
performs	O
packet	B-Protocol
capture	I-Protocol
.	O
</s>
<s>
Packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
may	O
be	O
deployed	O
anywhere	O
on	O
a	O
network	O
,	O
however	O
,	O
most	O
commonly	O
are	O
placed	O
at	O
the	O
entrances	O
to	O
the	O
network	O
(	O
i.e.	O
</s>
<s>
In	O
general	O
,	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
capture	O
and	O
record	O
all	O
network	O
packets	O
in	O
full	O
(	O
both	O
header	O
and	O
payload	O
)	O
,	O
however	O
,	O
some	O
appliances	O
may	O
be	O
configured	O
to	O
capture	O
a	O
subset	O
of	O
a	O
network	O
's	O
traffic	O
based	O
on	O
user-definable	O
filters	O
.	O
</s>
<s>
For	O
many	O
applications	O
,	O
especially	O
network	B-Protocol
forensics	I-Protocol
and	O
incident	O
response	O
,	O
it	O
is	O
critical	O
to	O
conduct	O
full	O
packet	B-Protocol
capture	I-Protocol
,	O
though	O
filtered	O
packet	B-Protocol
capture	I-Protocol
may	O
be	O
used	O
at	O
times	O
for	O
specific	O
,	O
limited	O
information	O
gathering	O
purposes	O
.	O
</s>
<s>
The	O
network	O
data	O
that	O
a	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
captures	O
depends	O
on	O
where	O
and	O
how	O
the	O
appliance	O
is	O
installed	O
on	O
a	O
network	O
.	O
</s>
<s>
There	O
are	O
two	O
options	O
for	O
deploying	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
on	O
a	O
network	O
.	O
</s>
<s>
One	O
option	O
is	O
to	O
connect	O
the	O
appliance	O
to	O
the	O
SPAN	B-Protocol
port	I-Protocol
(	O
port	B-Protocol
mirroring	I-Protocol
)	O
on	O
a	O
network	B-Protocol
switch	I-Protocol
or	O
router	O
.	O
</s>
<s>
A	O
second	O
option	O
is	O
to	O
connect	O
the	O
appliance	O
inline	O
,	O
so	O
that	O
network	O
activity	O
along	O
a	O
network	O
route	O
traverses	O
the	O
appliance	O
(	O
similar	O
in	O
configuration	O
to	O
a	O
network	B-Device
tap	I-Device
,	O
but	O
the	O
information	O
is	O
captured	O
and	O
stored	O
by	O
the	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
rather	O
than	O
passing	O
on	O
to	O
another	O
device	O
)	O
.	O
</s>
<s>
When	O
connected	O
via	O
a	O
SPAN	B-Protocol
port	I-Protocol
,	O
the	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
may	O
receive	O
and	O
record	O
all	O
Ethernet/IP	O
activity	O
for	O
all	O
of	O
the	O
ports	O
of	O
the	O
switch	O
or	O
router	O
.	O
</s>
<s>
When	O
connected	O
inline	O
,	O
the	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
captures	O
only	O
the	O
network	O
traffic	O
traveling	O
between	O
two	O
points	O
,	O
that	O
is	O
,	O
traffic	O
that	O
passes	O
through	O
the	O
cable	O
to	O
which	O
the	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
is	O
connected	O
.	O
</s>
<s>
There	O
are	O
two	O
general	O
approaches	O
to	O
deploying	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
:	O
centralized	O
and	O
decentralized	O
.	O
</s>
<s>
With	O
a	O
centralized	O
approach	O
,	O
one	O
high-capacity	O
,	O
high-speed	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
connects	O
to	O
a	O
data-aggregation	O
point	O
.	O
</s>
<s>
In	O
the	O
past	O
,	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
were	O
sparingly	O
deployed	O
,	O
oftentimes	O
only	O
at	O
the	O
point	O
of	O
entry	O
into	O
a	O
network	O
.	O
</s>
<s>
Packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
can	O
now	O
be	O
deployed	O
more	O
effectively	O
at	O
various	O
points	O
around	O
the	O
network	O
.	O
</s>
<s>
By	O
placing	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
at	O
the	O
entry	O
point	O
and	O
in	O
front	O
of	O
each	O
work	O
group	O
,	O
following	O
the	O
path	O
of	O
a	O
particular	O
transmission	O
deeper	O
into	O
the	O
network	O
would	O
be	O
simplified	O
and	O
much	O
quicker	O
.	O
</s>
<s>
Packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
come	O
with	O
capacities	O
ranging	O
from	O
500	O
GB	O
to	O
192	O
TB	O
and	O
more	O
.	O
</s>
<s>
Full	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
capture	O
and	O
record	O
all	O
Ethernet/IP	O
activity	O
,	O
while	O
filtered	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
capture	O
only	O
a	O
subset	O
of	O
traffic	O
based	O
on	O
a	O
set	O
of	O
user-definable	O
filters	O
;	O
such	O
as	O
IP	B-Protocol
address	I-Protocol
,	O
MAC	O
address	O
or	O
protocol	O
.	O
</s>
<s>
Unless	O
using	O
the	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
for	O
a	O
very	O
specific	O
purpose	O
covered	O
by	O
the	O
filter	O
parameters	O
,	O
it	O
is	O
generally	O
best	O
to	O
use	O
full	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
or	O
otherwise	O
risk	O
missing	O
vital	O
data	O
.	O
</s>
<s>
Particularly	O
when	O
using	O
a	O
packet	B-Protocol
capture	I-Protocol
for	O
network	B-Protocol
forensics	I-Protocol
or	O
cybersecurity	O
purposes	O
,	O
it	O
is	O
paramount	O
to	O
capture	O
everything	O
because	O
any	O
packet	O
not	O
captured	O
on	O
the	O
spot	O
is	O
a	O
packet	O
that	O
is	O
gone	O
forever	O
.	O
</s>
<s>
Intelligent	O
packet	B-Protocol
capture	I-Protocol
uses	O
machine	O
learning	O
to	O
filter	O
and	O
reduce	O
the	O
amount	O
of	O
network	O
traffic	O
captured	O
.	O
</s>
<s>
Traditional	O
filtered	O
packet	B-Protocol
capture	I-Protocol
relies	O
on	O
rules	O
and	O
policies	O
which	O
are	O
manually	O
configured	O
to	O
capture	O
all	O
potentially	O
malicious	O
traffic	O
.	O
</s>
<s>
Intelligent	O
packet	B-Protocol
capture	I-Protocol
uses	O
machine	O
learning	O
models	O
,	O
including	O
features	O
from	O
Cyber	O
threat	O
intelligence	O
feeds	O
,	O
to	O
scientifically	O
target	O
and	O
capture	O
the	O
most	O
threatening	O
traffic	O
.	O
</s>
<s>
Some	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
encrypt	O
the	O
captured	O
data	O
before	O
saving	O
it	O
to	O
disk	O
,	O
while	O
others	O
do	O
not	O
.	O
</s>
<s>
The	O
sustained	O
captured	O
speed	O
is	O
the	O
rate	O
at	O
which	O
a	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
can	O
capture	O
and	O
record	O
packets	O
without	O
interruption	O
or	O
error	O
over	O
a	O
long	O
period	O
of	O
time	O
.	O
</s>
<s>
This	O
is	O
different	O
from	O
the	O
peak	O
capture	O
rate	O
,	O
which	O
is	O
the	O
highest	O
speed	O
at	O
which	O
a	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
can	O
capture	O
and	O
record	O
packets	O
.	O
</s>
<s>
Many	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
share	O
the	O
same	O
peak	O
capture	O
speed	O
of	O
1	O
Gbit/s	O
,	O
but	O
actual	O
sustained	O
speeds	O
vary	O
significantly	O
from	O
model	O
to	O
model	O
.	O
</s>
<s>
A	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
with	O
permanent	O
storage	O
is	O
ideal	O
for	O
network	B-Protocol
forensics	I-Protocol
and	O
permanent	O
record-keeping	O
purposes	O
because	O
the	O
data	O
captured	O
cannot	O
be	O
overwritten	O
,	O
altered	O
or	O
deleted	O
.	O
</s>
<s>
Packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
with	O
overwritable	O
storage	O
are	O
easier	O
to	O
manage	O
because	O
once	O
they	O
reach	O
capacity	O
they	O
will	O
start	O
overwriting	O
the	O
oldest	O
captured	O
data	O
with	O
the	O
new	O
,	O
however	O
,	O
network	O
administrators	O
run	O
the	O
risk	O
of	O
losing	O
important	O
capture	O
data	O
when	O
it	O
gets	O
overwritten	O
.	O
</s>
<s>
In	O
general	O
,	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
with	O
overwrite	O
capabilities	O
are	O
useful	O
for	O
simple	O
monitoring	O
or	O
testing	O
purposes	O
,	O
for	O
which	O
a	O
permanent	O
record	O
is	O
not	O
necessary	O
.	O
</s>
<s>
Permanent	O
,	O
non-overwritable	O
recording	O
is	O
a	O
must	O
for	O
network	B-Protocol
forensics	I-Protocol
information	O
gathering	O
.	O
</s>
<s>
If	O
a	O
business	O
intends	O
to	O
use	O
one	O
centralized	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
to	O
aggregate	O
all	O
network	O
data	O
,	O
it	O
would	O
probably	O
be	O
necessary	O
to	O
use	O
a	O
10	O
GbE	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
to	O
handle	O
the	O
large	O
volume	O
of	O
data	O
coming	O
to	O
it	O
from	O
all	O
over	O
the	O
network	O
.	O
</s>
<s>
A	O
more	O
effective	O
way	O
is	O
to	O
use	O
multiple	O
1	O
Gbit/s	O
inline	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
placed	O
strategically	O
around	O
the	O
network	O
so	O
that	O
there	O
is	O
no	O
need	O
to	O
re-engineer	O
a	O
gigabit	O
network	O
to	O
fit	O
a	O
10	O
GbE	O
appliance	O
.	O
</s>
<s>
Since	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
capture	O
and	O
store	O
a	O
large	O
amount	O
of	O
data	O
on	O
network	O
activity	O
,	O
including	O
files	O
,	O
emails	O
and	O
other	O
communications	O
,	O
they	O
could	O
,	O
in	O
themselves	O
,	O
become	O
attractive	O
targets	O
for	O
hacking	O
.	O
</s>
<s>
A	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
deployed	O
for	O
any	O
length	O
of	O
time	O
should	O
incorporate	O
security	O
features	O
,	O
to	O
protect	O
the	O
recorded	O
network	O
data	O
from	O
access	O
by	O
unauthorized	O
parties	O
.	O
</s>
<s>
If	O
deploying	O
a	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
introduces	O
too	O
many	O
additional	O
concerns	O
about	O
security	O
,	O
the	O
cost	O
of	O
securing	O
it	O
may	O
outweigh	O
the	O
benefits	O
.	O
</s>
<s>
The	O
best	O
approach	O
would	O
be	O
for	O
the	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
to	O
have	O
built-in	O
security	O
features	O
.	O
</s>
<s>
For	O
example	O
,	O
some	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
feature	O
“	O
electronic	O
invisibility	O
”	O
,	O
where	O
they	O
have	O
a	O
stealthy	O
network	O
profile	O
by	O
not	O
requiring	O
or	O
using	O
IP	O
nor	O
MAC	O
addresses	O
.	O
</s>
<s>
Though	O
connecting	O
a	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
via	O
a	O
SPAN	B-Protocol
port	I-Protocol
appears	O
to	O
make	O
it	O
more	O
secure	O
,	O
the	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
would	O
ultimately	O
still	O
have	O
to	O
be	O
connected	O
to	O
the	O
network	O
in	O
order	O
to	O
allow	O
management	O
and	O
data	O
retrieval	O
.	O
</s>
<s>
Despite	O
the	O
benefits	O
,	O
the	O
ability	O
to	O
control	O
a	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
from	O
a	O
remote	O
machine	O
presents	O
a	O
security	O
issue	O
that	O
could	O
make	O
the	O
appliance	O
vulnerable	O
.	O
</s>
<s>
Packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
that	O
allow	O
remote	O
access	O
should	O
have	O
a	O
robust	O
system	O
in	O
place	O
to	O
protect	O
it	O
against	O
unauthorized	O
access	O
.	O
</s>
<s>
All	O
the	O
network	O
security	O
features	O
in	O
the	O
world	O
are	O
moot	O
if	O
someone	O
is	O
simply	O
able	O
to	O
steal	O
the	O
packet	B-Protocol
capture	I-Protocol
appliance	I-Protocol
or	O
make	O
a	O
copy	O
of	O
it	O
and	O
have	O
ready	O
access	O
to	O
the	O
data	O
stored	O
on	O
it	O
.	O
</s>
<s>
Encryption	O
is	O
one	O
of	O
the	O
best	O
ways	O
to	O
address	O
this	O
concern	O
,	O
though	O
some	O
packet	B-Protocol
capture	I-Protocol
appliances	I-Protocol
also	O
feature	O
tamperproof	O
enclosures	O
.	O
</s>
