<s>
A	O
jump	B-Architecture
server	I-Architecture
,	O
jump	B-Architecture
host	I-Architecture
or	O
jump	B-Architecture
box	I-Architecture
is	O
a	O
system	O
on	O
a	O
network	B-Architecture
used	O
to	O
access	O
and	O
manage	O
devices	O
in	O
a	O
separate	O
security	O
zone	O
.	O
</s>
<s>
A	O
jump	B-Architecture
server	I-Architecture
is	O
a	O
hardened	O
and	O
monitored	O
device	O
that	O
spans	O
two	O
dissimilar	O
security	O
zones	O
and	O
provides	O
a	O
controlled	O
means	O
of	O
access	O
between	O
them	O
.	O
</s>
<s>
The	O
most	O
common	O
example	O
is	O
managing	O
a	O
host	O
in	O
a	O
DMZ	B-General_Concept
from	O
trusted	O
networks	O
or	O
computers	O
.	O
</s>
<s>
The	O
jump	B-Architecture
server	I-Architecture
concept	O
emerged	O
to	O
meet	O
this	O
need	O
.	O
</s>
<s>
The	O
jump	B-Architecture
server	I-Architecture
would	O
span	O
the	O
two	O
networks	O
and	O
typically	O
be	O
used	O
in	O
conjunction	O
with	O
a	O
proxy	O
service	O
such	O
as	O
SOCKS	B-Application
to	O
provide	O
access	O
from	O
an	O
administrative	O
desktop	O
to	O
the	O
managed	O
device	O
.	O
</s>
<s>
As	O
SSH-based	O
tunneling	O
became	O
common	O
,	O
jump	B-Architecture
servers	I-Architecture
became	O
the	O
de	O
facto	O
method	O
of	O
access	O
.	O
</s>
<s>
Jump	B-Architecture
servers	I-Architecture
are	O
often	O
placed	O
between	O
a	O
secure	O
zone	O
and	O
a	O
DMZ	B-General_Concept
to	O
provide	O
transparent	O
management	O
of	O
devices	O
on	O
the	O
DMZ	B-General_Concept
once	O
a	O
management	O
session	O
has	O
been	O
established	O
.	O
</s>
<s>
The	O
jump	B-Architecture
server	I-Architecture
acts	O
as	O
a	O
single	O
audit	O
point	O
for	O
traffic	O
and	O
also	O
a	O
single	O
place	O
where	O
user	O
accounts	O
can	O
be	O
managed	O
.	O
</s>
<s>
A	O
prospective	O
administrator	O
must	O
log	O
into	O
the	O
jump	B-Architecture
server	I-Architecture
in	O
order	O
to	O
gain	O
access	O
to	O
the	O
DMZ	B-General_Concept
assets	O
and	O
all	O
access	O
can	O
be	O
logged	O
for	O
later	O
audit	O
.	O
</s>
<s>
A	O
typical	O
configuration	O
is	O
a	O
hardened	O
Unix	O
(	O
or	O
Unix-like	B-Operating_System
)	O
machine	O
configured	O
with	O
SSH	B-Protocol
and	O
a	O
local	O
firewall	B-Application
.	O
</s>
<s>
An	O
administrator	O
connects	O
to	O
a	O
target	O
machine	O
in	O
the	O
DMZ	B-General_Concept
by	O
making	O
an	O
SSH	B-Protocol
connection	O
from	O
the	O
administrator	O
's	O
personal	O
computer	O
to	O
the	O
jump	B-Architecture
server	I-Architecture
and	O
then	O
using	O
SSH	B-Protocol
forwarding	O
to	O
access	O
the	O
target	O
machine	O
.	O
</s>
<s>
Using	O
SSH	B-Protocol
port	O
forwarding	O
or	O
an	O
SSH-based	O
tunnel	O
to	O
the	O
target	O
host	O
allows	O
the	O
use	O
of	O
insecure	O
protocols	O
to	O
manage	O
servers	O
without	O
creating	O
special	O
firewall	B-Application
rules	O
or	O
exposing	O
the	O
traffic	O
on	O
the	O
inside	O
network	B-Architecture
.	O
</s>
<s>
A	O
typical	O
configuration	O
is	O
a	O
Windows	O
server	O
running	O
Remote	B-Protocol
Desktop	I-Protocol
Services	I-Protocol
that	O
administrators	O
connect	O
to	O
,	O
this	O
isolates	O
the	O
secure	O
infrastructure	O
from	O
the	O
configuration	O
of	O
the	O
administrator	O
's	O
workstation	O
.	O
</s>
<s>
A	O
jump	B-Architecture
server	I-Architecture
is	O
a	O
potential	O
risk	O
in	O
a	O
network	B-Architecture
's	O
design	O
.	O
</s>
<s>
There	O
are	O
several	O
ways	O
of	O
improving	O
the	O
security	O
of	O
the	O
jump	B-Architecture
server	I-Architecture
,	O
including	O
:	O
</s>
<s>
Properly	O
subnetting	O
/	O
segmenting	O
the	O
network	B-Architecture
,	O
and	O
securing	O
VLANs	B-General_Concept
using	O
a	O
firewall	B-Application
or	O
router	O
.	O
</s>
<s>
Keeping	O
the	O
operating	O
system	O
and	O
software	O
on	O
the	O
jump	B-Architecture
server	I-Architecture
up	O
to	O
date	O
.	O
</s>
<s>
Not	O
allowing	O
outbound	O
access	O
to	O
the	O
rest	O
of	O
the	O
internet	O
from	O
the	O
jump	B-Architecture
server	I-Architecture
.	O
</s>
<s>
Restricting	O
which	O
programs	O
can	O
be	O
run	O
on	O
the	O
jump	B-Architecture
server	I-Architecture
.	O
</s>
<s>
With	O
the	O
high	O
level	O
of	O
risk	O
that	O
a	O
jump	B-Architecture
server	I-Architecture
can	O
represent	O
,	O
a	O
VPN	B-Application
may	O
be	O
a	O
suitable	O
and	O
higher	O
security	O
replacement	O
.	O
</s>
<s>
In	O
2015	O
,	O
a	O
compromised	O
jump	B-Architecture
server	I-Architecture
allowed	O
attackers	O
access	O
to	O
over	O
21.5	O
million	O
records	O
in	O
one	O
of	O
the	O
largest	O
breaches	O
of	O
government	O
data	O
in	O
the	O
history	O
of	O
the	O
United	O
States	O
.	O
</s>
