Modbus
Cellular
Gateway
Index
skipping
is
used
to
reserve
slots
for
new
function
insertion,
when
required.
104
3.9.3
Virtual
Server
&
Virtual
Computer
Virtual
server
is
another
name
for
port
forwarding
used
by
some
routers.
In
computer
networking,
port
forwarding
or
port
mapping
is
an
application
of
network
address
translation
(NAT)
that
redirects
a
communication
request
from
one
address
and
port
number
combination
to
another
while
the
packets
are
traversing
a
network
gateway,
such
as
a
router
or
firewall.
This
technique
is
most
commonly
used
to
make
services
on
a
host
residing
on
a
protected
or
masqueraded
(internal)
network
available
to
hosts
on
the
opposite
side
of
the
gateway
(external
network),
by
remapping
the
destination
IP
address
and
port
number
of
the
communication
to
an
internal
host.
Port
forwarding
allows
remote
computers
(a
computers
on
the
Internet)
to
connect
to
a
specific
computer
or
service
within
a
private
local
‐
area
network
(LAN).
So
you
can
deploy
some
servers
in
your
Intranet
with
the
firewall
protection
by
your
gateway.
This
device’s
NAT
firewall
filters
out
unrecognized
packets
to
protect
your
Intranet,
so
all
hosts
behind
this
device
gateway
are
invisible
to
the
outside
world.
If
you
wish,
you
can
make
some
of
them
accessible
by
enabling
the
Virtual
Server
Mapping.
However,
a
virtual
computer
is
a
host
in
the
Intranet
whose
IP
address
is
global
and
is
visible
to
the
outside
world.
Since
it
is
in
the
Intranet,
it
is
protected
by
the
firewall
gateway
when
it
acts
like
a
node
in
the
Internet.
In
"Virtual
Server
&
Virtual
Computer"
page,
there
are
two
list
windows
for
all
virtual
servers
and
virtual
computer.
"Virtual
Server
List"
window
lists
the
public
port
used
in
the
Internet,
server
IP
at
LAN
side,
private
port
used
in
the
Intranet,
used
protocol
for
the
service
on
the
server
and
the
integrated
time
schedule
rule
for
all
virtual
servers.
There
is
an
"Add"
button
for
you
to
add
and
create
new
virtual
server,
and
the
"Edit"
button
to
modify
the
existed
virtual
server
settings.
On
"Virtual
Computer
List"
window,
the
mapping
of
the
global
IP
address
and
the
local
IP
address
for
all
virtual
computers
are
listed.
There
is
also
a
"Add"
button
for
you
to
add
and
create
new
virtual
computer,
and
the
"Edit"
button
to
modify
the
existed
virtual
computer.
