© Microhard Systems Inc.
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Appendix B: IP-Passthrough Example (Page 1 of 2)
By completing the Quick Start process, a user should have been able to log in and set up the
IPn4G
to
work with their cellular carrier. By completing this, the modem is ready to be used to access the internet
and provide mobile connectivity. However, a common application of the
IPn4G
is to access connected
devices remotely. In order to do this, the
IPn4G
must be told how to deal with incoming traffic, where to
send it to. To accomplish this there are three options :
- IP-Passthrough
- Port Forwarding
- DMZ (a type of Port Forwarding)
In this section we will talk about IP-Passthrough and how to configure the IPn4G and the connected
device/PC to work with IP-Passthrough. IP-Passthrough means that the IPn4G is transparent, and all
outside (WAN) traffic is simply sent directly to a single device connected to the physical LAN RJ-45 port on
the IPn4G (With exception of port 80, which is retained for remote configuration (configurable). Also, any
traffic that is sent to the RJ45 port is sent directly out the WAN port and is not processed by the IPn4G.
IP-Passthrough is ideal for applications where only a single device is connected to the IPn4G, and other
features of the IPn4G are not required. When in pass-through mode, most features of the IPn4G are
bypassed, this includes the serial ports, the GPS features, VPN, the Firewall, and much more. The
advantage of IP-Passthrough is that the configuration is very simple.
In the example below we have a IPn4G connected to a PC (PC2). The application requires that PC1 be
able to access several services on PC2. Using Port Forwarding this would require a new rule created for
each port, and some applications or services may require several ports so this would require several rules,
and the rules may be different for each installation, making future maintenance difficult. For IP-
Passthrough, PC1 only needs to know the Public Static IP Address of the IPn4G, the IPn4G would then
automatically assign, via DHCP, the WAN IP to the attached PC2, creating a transparent connection.
Step 1
Log into the IPn4G (Refer to Quick Start), and ensure that DHCP is
enabled on the
Network > LAN
page.
Step 2
Since PC2 requires port 80 to be used as its Web server port, port
80 cannot be used on the IPn4G, by default it retains this port for
remote configuration. To change the port used by the IPn4G,
navigate to the
System > Settings
page as seen below. For this
example we are going to change it to port 8080. When changing
port numbers on the IPn4G, it is recommended to reboot the unit
before continuing, remember the new WebUI port is now 8080 when
you log back into the IPn4G. (e.g. 192.168.168.1:8080).
Cellular Network/
Internet
WAN IP: 74.198.186.193
(Cellular Carrier)
LAN IP: 74.198.186.1 (Used
for WebUI from LAN)
PC2: (DHCP)
WebServer running on port 80
Connected to RJ45
LAN Ethernet Port.
Wireless Cellular
Connection
PC1: Connected to
internet.
