<s>
Network	B-General_Concept
enumeration	I-General_Concept
is	O
a	O
computing	O
activity	O
in	O
which	O
usernames	O
and	O
info	O
on	O
groups	O
,	O
shares	O
,	O
and	O
services	O
of	O
networked	B-Architecture
computers	I-Architecture
are	O
retrieved	O
.	O
</s>
<s>
It	O
should	O
not	O
be	O
confused	O
with	O
network	B-Architecture
mapping	I-Architecture
,	O
which	O
only	O
retrieves	O
information	O
about	O
which	O
servers	B-Application
are	O
connected	O
to	O
a	O
specific	O
network	B-Architecture
and	O
what	O
operating	B-General_Concept
system	I-General_Concept
runs	O
on	O
them	O
.	O
</s>
<s>
Network	B-General_Concept
enumeration	I-General_Concept
is	O
the	O
discovery	O
of	O
hosts	B-Device
or	O
devices	O
on	O
a	O
network	B-Architecture
.	O
</s>
<s>
Network	B-General_Concept
enumeration	I-General_Concept
tends	O
to	O
use	O
overt	O
discovery	O
protocols	O
such	O
as	O
ICMP	B-Protocol
and	O
SNMP	B-Protocol
to	O
gather	O
information	O
.	O
</s>
<s>
It	O
may	O
also	O
scan	O
various	O
ports	O
on	O
remote	O
hosts	B-Device
for	O
looking	O
for	O
well	O
known	O
services	O
in	O
an	O
attempt	O
to	O
further	O
identify	O
the	O
function	O
of	O
a	O
remote	O
host	O
.	O
</s>
<s>
The	O
next	O
stage	O
of	O
enumeration	O
is	O
to	O
fingerprint	B-Protocol
the	O
operating	B-General_Concept
system	I-General_Concept
of	O
the	O
remote	O
host	O
.	O
</s>
<s>
A	O
network	B-General_Concept
enumerator	I-General_Concept
or	O
network	B-General_Concept
scanner	I-General_Concept
is	O
a	O
computer	B-Application
program	I-Application
used	O
to	O
retrieve	O
usernames	O
and	O
info	O
on	O
groups	O
,	O
shares	O
,	O
and	O
services	O
of	O
networked	B-Architecture
computers	I-Architecture
.	O
</s>
<s>
This	O
type	O
of	O
program	O
scans	O
networks	O
for	O
vulnerabilities	O
in	O
the	O
security	O
of	O
that	O
network	B-Architecture
.	O
</s>
<s>
If	O
there	O
is	O
a	O
vulnerability	O
with	O
the	O
security	O
of	O
the	O
network	B-Architecture
,	O
it	O
will	O
send	O
a	O
report	O
back	O
to	O
a	O
hacker	O
who	O
may	O
use	O
this	O
info	O
to	O
exploit	O
that	O
network	B-Architecture
glitch	O
to	O
gain	O
entry	O
to	O
the	O
network	B-Architecture
or	O
for	O
other	O
malicious	O
activities	O
.	O
</s>
<s>
Ethical	O
hackers	O
often	O
also	O
use	O
the	O
information	O
to	O
remove	O
the	O
glitches	O
and	O
strengthen	O
their	O
network	B-Architecture
.	O
</s>
<s>
Malicious	O
(	O
or	O
"	O
black-hat	O
"	O
)	O
hackers	O
can	O
,	O
on	O
entry	O
of	O
the	O
network	B-Architecture
,	O
get	O
to	O
security-sensitive	O
information	O
or	O
corrupt	O
the	O
network	B-Architecture
making	O
it	O
useless	O
.	O
</s>
<s>
If	O
this	O
network	B-Architecture
belonged	O
to	O
a	O
company	O
which	O
used	O
this	O
network	B-Architecture
on	O
a	O
regular	O
basis	O
,	O
the	O
company	O
would	O
lose	O
the	O
function	O
to	O
send	O
information	O
internally	O
to	O
other	O
departments	O
.	O
</s>
<s>
Network	B-General_Concept
enumerators	I-General_Concept
are	O
often	O
used	O
by	O
script	O
kiddies	O
for	O
ease	O
of	O
use	O
,	O
as	O
well	O
as	O
by	O
more	O
experienced	O
hackers	O
in	O
cooperation	O
with	O
other	O
programs/manual	O
lookups	O
.	O
</s>
<s>
Also	O
,	O
whois	B-Protocol
queries	O
,	O
zone	B-Protocol
transfers	I-Protocol
,	O
ping	B-Protocol
sweeps	I-Protocol
,	O
and	O
traceroute	B-Protocol
can	O
be	O
performed	O
.	O
</s>
