ReCon T Energy Logger
User manual
Accessing ReCon T from outside the LAN. Router's NAT
configuration.
If the administrator´s computer is out side the L AN, the NAT (Network Address Translation) table of
the LAN´s router must be setup to redirect ports (
http://en.wikipedia.org/wiki/Network_address_translation
).
To understand the added complication, user must be aware of that all the incoming and outgoing
traffic of an office or facility network (all the d at a from network computer´s web browsers, email software
…) goes through the unique public IP address of the router (WAN IP address). That is to say that the only
visible IP address from out side the office or facility is the router ´ s public address (which can be easily
guessed searching for “my public IP address” in Google or detected in the router´s configuration utility if the
router is DHCP configured, or must be provided by the ISP –internet server provider, from whom you rent
your internet connection- if a static IP address is rented). Routers are in charge of redirecting incoming data
to the local computers (local IP addresses) that requested the data. But if the incoming data is not a response
to an outgoing request but a connection from the administrator´s computer (via MedcalScope, Modbus
software or web browser), there is no other way to redirect traffic apart from configuring the NAT table. This
configuration consists just in telling the router to which local IP address and port it must redirect the
incoming traffic from a certain port.
In the example below, we are telling the router to redirect the incoming data that comes from port
23502 to the port 502 of the address 192.168.0.23, which could correspond to a ReCon T configured to be
accessed via ModBus.
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Figure 16: Router´s status page: detect WAN (public) IP address
