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accessing device connected in eth0

Fri Jan 11, 2019 6:31 pm


I am trying to solve the following problem.
I have a TCP / Modbus device connected to the eth0 of my rasp. The wla0 interface is connected to a router with internet access.
Through a VPN (https://www.dynvpn.com) I am accessing by accessing my raspberry, this service provides me an IP, example and through my PC (windows) with IP I can access the rasp in different networks.
My goal is to access the device that is in eth0, any suggestions?


any suggestions are welcome!


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Re: accessing device connected in eth0

Fri Jan 11, 2019 7:07 pm

Two spring to mind but search further for full details on how to do them:
  • A NAT firewall on the Pi with suitable port forwarding for the device on eth0
  • Bridge the Pi's wifi and ethernet interfaces.
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Re: accessing device connected in eth0

Fri Jan 11, 2019 7:30 pm

In general, a good VPN will create a local virtual network device, and sand-boxed networks.
After a client connects to the tunnel, a local IP is assigned for each remote user in the sand-boxed network.
The admin must then decide how to route packets between the sand-boxed area, and other actual LAN areas.
Note, this setup may require manually editing the routing tables rules, checking the clients gateway configuration, and ensuring VPN/IPsec is supported by the routers on each end of the tunnel.
It is very easy to get wrong, which is why CISCO is still in business ;-)

Note modbus/tcp is similar to the era of telnet/FTP, and is notoriously difficult to reliably secure.
Also, running industrial machinery over wifi is a really bad idea from a safety standpoint.

Best of Luck,

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