Xylem 19-001-350R2 PACE Integrated Pump Controller Human Machine Interface (HMI) for the Silent Storm VFD Pumping System – Technician Guide - Manual (Page 52)

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Generally, the WAN port of the pump station router is connected directly to the cable or DSL
modem, so the complex routing configuration is not required. The pump station router is usually
configured as follows:
Pump Station Router
WAN 76.199.50.60 (Supplied by internet service provider)
LAN 192.168.1.1
Port
Forwarding 80->192.168.1.15:80
81->192.168.1.16:80
82->192.168.1.17:80
Flowtronex is also capable of accessing the HMI and PLC in the pump station for diagnostic and
programming purposes, with the aid of personnel onsite. This requires access to additional ports
in the same way. Normally Flowtronex disables these ports in the pump station router to provide
extra security, but can enable and disable this port forwarding for service. To support this
capability, the IT department would need to provide a pathway into our router. Flowtronex will
map the final port forwarding in the pump station router as required, so all the IT department
would need to do is map through two unused ports to our router. The first example above is
recreated below as an example.
Router 1 Router 2 Pump Station Router
WAN 76.199.50.60 10.92.168.10 192.168.0.12
LAN 10.92.168.1 192.168.0.1 192.168.1.1
Port
Forwarding 80->10.92.168.10:80 80->192.168.0.12:80 80->192.168.1.15:80
8080->10.92.168.10:8080 8080->192.168.0.12:8080 None (Router Configuration)
9000->10.92.168.10:9000 9000->192.168.0.12:9000 Programming:Not routed until
needed
9001->10.92.168.10:9000 9001->192.168.0.12:9001 Programming:Not routed until
needed
Flowtronex will access the router configuration and port-forward as needed for the specific case,
then after programming is complete, disable the port forwarding for security.
One problem encountered occasionally is having the same IP address range on BOTH sides of a
router. That confuses the router. The Flowtronex pump station routers LAN side is set up at
192.168.1.x with a subnet mask of 255.255.255.0. That means all addresses 192.168.1.x are
assumed to be inside the network. If the router’s WAN side is assigned the address of
192.168.1.129, this will cause problems because the pump station router doesn’t know where its
LAN side ends (address wise) and where it begins. In that case, the pump station router will have
to be configured with a subnet mask to 15 and restrict our internal addresses to use only the
lower 4 bits for addressing. That could be a problem if there are devices on the network
addressed higher than 192.168.1.15 (i.e. auxiliary equipment, power monitors, etc). In such
cases, it may be required that we set the IP addresses in the equipment to another domain
altogether (192.168.200.x for example). This is a non-trivial operation.