Bell & Gossett 10-001-275 XLS Integrated Pump Controller - Manual (Page 50)

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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
Bell & Gossett 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 B e l l & G o s s e t t 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. Bell & Gossett 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
Bell & Gossett 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 Bell & Gossett 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.