Modbus
Cellular
Gateway
Index
skipping
is
used
to
reserve
slots
for
new
function
insertion,
when
required.
246
Scenario
Operation
Procedure
In
above
diagram,
Network
‐
A
is
in
the
headquarters,
and
the
subnet
of
its
Intranet
is
10.0.76.0/24.
The
security
gateway
for
Network
‐
A
has
the
IP
address
of
10.0.76.2
for
LAN
interface
and
203.95.80.22
for
WAN
interface.
It
serves
as
a
L2TP
server.
However,
Network
‐
B
is
in
the
mobile
office
and
the
subnet
of
its
Intranet
is
10.0.75.0/24.
The
security
gateway
for
Network
‐
B
has
the
IP
address
of
10.0.75.2
for
LAN
interface
and
118.18.81.33
for
WAN
interface.
It
serves
as
a
L2TP
client.
The
L2TP
client
uses
"User
‐
1"
user
account
to
dial
in
the
L2TP
server
at
HQ
for
establishing
a
L2TP
VPN
tunnel.
So
both
Intranets
of
10.0.75.0/24
and
10.0.76.0/24
can
securely
communicate
each
other.
Finally,
the
client
hosts
in
the
Intranet
of
Network
‐
B
at
mobile
office
can
access
the
server
or
database
resources
in
the
Intranet
of
Network
‐
A
at
HQ
in
a
secured
link.
However,
if
the
"Default
Gateway/Remote
Subnet"
parameter
in
the
Security
Gateway
2
is
configured
to
"Default
Gateway",
the
Internet
accessing
of
L2TP
Client
peer
also
go
through
the
established
L2TP
VPN
tunnel,
and
the
Security
Gateway
1
can
control
the
accessing
as
same
as
the
HQ
resource
accessing.
The
L2TP
allows
user
to
configure
L2TP
tunnel
Ensure
Configuration
are
enabled
and
saved
Go
to
Advanced
Network
>
VPN
>
L2TP
When
select
Server
in
Client/Server,
the
L2TP
server
Configuration
will
appear.
