<s>
A	O
rogue	B-Protocol
DHCP	I-Protocol
server	I-Protocol
is	O
a	O
DHCP	B-Protocol
server	I-Protocol
on	O
a	O
network	O
which	O
is	O
not	O
under	O
the	O
administrative	O
control	O
of	O
the	O
network	O
staff	O
.	O
</s>
<s>
It	O
is	O
a	O
network	O
device	O
such	O
as	O
a	O
modem	B-Application
or	O
a	O
router	B-Protocol
connected	O
to	O
the	O
network	O
by	O
a	O
user	O
who	O
may	O
be	O
either	O
unaware	O
of	O
the	O
consequences	O
of	O
their	O
actions	O
or	O
may	O
be	O
knowingly	O
using	O
it	O
for	O
network	O
attacks	O
such	O
as	O
man	O
in	O
the	O
middle	O
.	O
</s>
<s>
Some	O
kind	O
of	O
computer	O
viruses	O
or	O
malicious	O
software	O
have	O
been	O
found	O
to	O
set	O
up	O
a	O
rogue	B-Protocol
DHCP	I-Protocol
,	O
especially	O
for	O
those	O
classified	O
in	O
the	O
category	O
.	O
</s>
<s>
As	O
clients	O
connect	O
to	O
the	O
network	O
,	O
both	O
the	O
rogue	O
and	O
legal	O
DHCP	B-Protocol
server	I-Protocol
will	O
offer	O
them	O
IP	B-Protocol
addresses	I-Protocol
as	O
well	O
as	O
default	B-Protocol
gateway	I-Protocol
,	O
DNS	B-Protocol
servers	O
,	O
WINS	B-Device
servers	I-Device
,	O
among	O
others	O
.	O
</s>
<s>
If	O
the	O
information	O
provided	O
by	O
the	O
rogue	B-Protocol
DHCP	I-Protocol
differs	O
from	O
the	O
real	O
one	O
,	O
clients	O
accepting	O
IP	B-Protocol
addresses	I-Protocol
from	O
it	O
may	O
experience	O
network	O
access	O
problems	O
,	O
including	O
speed	O
issues	O
as	O
well	O
as	O
inability	O
to	O
reach	O
other	O
hosts	O
because	O
of	O
incorrect	O
IP	O
network	O
or	O
gateway	O
.	O
</s>
<s>
In	O
addition	O
,	O
if	O
a	O
rogue	B-Protocol
DHCP	I-Protocol
is	O
set	O
to	O
provide	O
as	O
default	B-Protocol
gateway	I-Protocol
an	O
IP	B-Protocol
address	I-Protocol
of	O
a	O
machine	O
controlled	O
by	O
a	O
misbehaving	O
user	O
,	O
it	O
can	O
sniff	O
all	O
the	O
traffic	O
sent	O
by	O
the	O
clients	O
to	O
other	O
networks	O
,	O
violating	O
network	O
security	O
policies	O
as	O
well	O
as	O
user	O
privacy	O
(	O
see	O
man	O
in	O
the	O
middle	O
)	O
.	O
</s>
<s>
VMware	O
or	O
virtual	O
machine	O
software	O
can	O
also	O
act	O
as	O
a	O
rogue	B-Protocol
DHCP	I-Protocol
server	I-Protocol
inadvertently	O
when	O
being	O
run	O
on	O
a	O
client	O
machine	O
joined	O
to	O
a	O
network	O
.	O
</s>
<s>
The	O
VMware	O
will	O
act	O
as	O
a	O
rogue	B-Protocol
DHCP	I-Protocol
server	I-Protocol
handing	O
out	O
random	O
IP	B-Protocol
addresses	I-Protocol
to	O
the	O
clients	O
around	O
it	O
on	O
the	O
network	O
.	O
</s>
<s>
Rogue	B-Protocol
DHCP	I-Protocol
servers	I-Protocol
can	O
be	O
stopped	O
by	O
means	O
of	O
intrusion	O
detection	O
systems	O
with	O
appropriate	O
signatures	O
,	O
as	O
well	O
as	O
by	O
some	O
multilayer	O
switches	O
,	O
which	O
can	O
be	O
configured	O
to	O
drop	O
the	O
packets	O
.	O
</s>
<s>
One	O
of	O
the	O
most	O
common	O
methods	O
to	O
deal	O
with	O
rogue	B-Protocol
DHCP	I-Protocol
servers	I-Protocol
is	O
called	O
DHCP	B-Protocol
snooping	I-Protocol
,	O
which	O
drops	O
DHCP	B-Protocol
messages	O
from	O
untrusted	O
DHCP	B-Protocol
servers	I-Protocol
.	O
</s>
