PoE
AP
Router
105
Virtual
Server
&
NAT
Loopback
"Virtual
Server"
allows
you
to
access
servers
with
the
global
IP
address
or
FQDN
of
the
gateway
as
if
they
are
servers
existed
in
the
Internet.
But
in
fact,
these
servers
are
located
in
the
Intranet
and
are
physically
behind
the
gateway.
The
gateway
serves
the
service
requests
by
port
forwarding
the
requests
to
the
LAN
servers
and
transfers
the
replies
from
LAN
servers
to
the
requester
on
the
WAN
side.
As
shown
in
example,
an
E
‐
virtual
server
is
defined
to
be
located
at
a
server
with
IP
address
10.0.75.101
in
the
Intranet
of
Network
‐
A,
including
SMTP
service
port
25
and
POP3
service
port
110.
So,
the
remote
user
can
access
the
E
‐
server
with
the
gateway’s
global
IP
118.18.81.33
from
its
WAN
side.
But
the
real
E
‐
server
is
located
at
LAN
side
and
the
gateway
is
the
port
forwarder
for
E
‐
service.
NAT
Loopback
allows
you
to
access
the
WAN
global
IP
address
from
your
inside
NAT
local
network.
It
is
useful
when
you
run
a
server
inside
your
network.
For
example,
if
you
set
a
server
at
LAN
side,
your
local
devices
can
access
this
server
through
gateway’s
global
IP
address
when
enable
NAT
loopback
feature.
On
either
side
are
you
in
accessing
the
server,
at
the
LAN
side
or
at
the
WAN
side,
you
don’t
need
to
change
the
IP
address
of
the
server.
Virtual
Computer
"Virtual
Computer"
allows
you
to
assign
LAN
hosts
to
global
IP
addresses,
so
that
they
can
be
visible
to
outside
world.
While
so,
they
are
also
protected
by
the
gateway
firewall
as
being
client
hosts
in
the
Intranet.
For
example,
if
you
set
a
FTP
file
server
at
LAN
side
with
local
IP
address
10.0.75.102
and
global
IP
address
118.18.82.44,
a
remote
user
can
access
the
file
server
while
it
is
hidden
behind
the
NAT
gateway.
That
is
because
the
gateway
takes
care
of
all
accessing
to
the
IP
address
118.18.82.44,
including
to
forward
the
access
requests
to
the
file
server
and
to
send
the
replies
from
the
server
to
outside
world
.
