User guide

eWON 500-2001-4001-4002 User Guide - eWON Configuration
eWON 500®2001®4001®4002® Version 4_3_0 - User Guide - 10/5/05 - ©ACT'L sa - Page 49
Control Description
Enable IP forwarding
If this box is checked, then the eWON IP forwarding feature is enabled. This means that a link
can be performed between PPP and Ethernet IP packets. Please note that this is dangerous
because it can connect your LAN to the internet directly.
This feature can be used in order to connect a device to the internet through the eWON. For
example, if an automaton is connected to the Ethernet LAN of the eWON and has the eWON
IP address as gateway address, the eWON will perform any thing needed in order for the
device to send its packets (dialout, IP translation …). Example: a device sends a mail on the
internet, while the eWON performs the PPP dial-out.
Another use is to access a device located on the Ethernet LAN of the eWON, the user dials
the eWON directly and then gains access to its distant device through its LAN IP address.
Example: a user on a LAN with IP address range 192.168.0.xxx can access its device on the
eWON LAN, with eWON IP address 10.0.0.81 and the distant device with IP 10.0.0.82 and
having the eWON as a gateway. The eWON will for example assign the IP address 202.0.0.1
to the PPP adapter of the PC and take for its PPP adapter the IP address 202.0.0.240.
Enable NAT
This feature enables the Network Address Translation (NAT). If the device to reach is on the
same LAN as the eWON, and if the user has correctly defined the address IP and the port for
this device, then the eWON will redirect the packets towards it. This means that only the
packets for the concerned port will be redirected towards the selected IP address. IP
Forwarding must be activated for NAT to be active.
Enable Transparent forwarding
If this box is checked, the transparent forwarding feature of the eWON is activated. For this to
work, the IP forwarding must also be enabled. With simple IP forwarding, it is not possible to
access a device located on the eWON Ethernet LAN through the internet. For example if the
eWON is connected to the internet through PPP (for example on alarm), it publishes its IP
address by Email. In order to get access to its device, the user cannot simply type the IP
address of the device like this was done with IP forwarding and direct eWON call.
In this case, transparent forwarding is the only solution: when accessing the eWON, the user
can request to perform transparent forwarding once he logs in. He can then see the window
that is illustrated by the screenshot below this table. If the device is on the same network as
the eWON and gets the eWON as gateway, and if the user configured the IP address of the
device at eWON login, the eWON routes all packets to this device.
This means that all IP packets, on all ports except 81 will be routed transparently to the
selected IP address. In order to get access to the eWON web server, the user has to connect
to port 81 of the eWON IP address. For example http://10.0.0.53:81
will access the eWON
main page, while 10.0.0.53 will access the IP address 10.0.0.56 of the device located onto the
LAN if the user selected this IP at logon. The user can clear transparent forwarding by getting
access to the port 81 and using the “Clear transp forwarding” button. Note that FTP cannot be
routed, since it includes the target IP address in its frame in text mode.
Authenticated routing
If this box is checked, the eWON will only accept to forward packets coming from the user
who initiated the communication.
Dial On Demand
It is possible to establish remote connections towards the ISP by using the Dial On Demand
feature. If selected, the eWON will then try to connect to the ISP each time a connection will
be required (i.e. packets to send). Those fields allow you EITHER to exclude OR to select IP
addresses ranges that are allowed or refused for Dial On Demand. Four different IP
addresses ranges can be defined.
Note: those fields will be updated at each every new PPP connection.
Table 27: router configuration controls