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Joined: Tue Aug 08, 2017 1:49 pm

Two ethernet connections, remote viewing

Tue Aug 08, 2017 2:36 pm

Apologies if this is the wrong forum, it's my first post.

I will try to be as concise as I can. I have tried to look for solutions and think I might have to use port forwarding.

I have an gas powered engine. The engine is connected to a router via an ethernet cable. The engine has a screen on with information regarding data and power etc

If I plug my laptop into the engine via ethernet, we have a HMI interface that we can use to duplicate the screen that is on the engine on the laptop.

I want to access this 'engine screen' remotely.

I have toyed with the idea of using a raspberry pi in the following setup.

I connect the pi to the engine via ethernet. I then connect the pi to the router via ethernet.

I then use VNCViewer on a different network, to view the pi and view the HMI interface to the engine.

I have read some great threads and guides on how to connect to a pi remotely which I feel very comfortable with.

My issue is, will the router and the engine both give my pi a different IP?

If anyone has any idea or suggestions they are much appreciated. If this is something that is not suited to this forum, then please forgive me and remove it!

Thanks in advance

Frank White

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Posts: 167
Joined: Wed Dec 28, 2016 9:21 pm

Re: Two ethernet connections, remote viewing

Wed Aug 09, 2017 5:45 am

We will need to dig into network technology here, so please allow me to ask some questions to get an understanding of your setup. This also allows others to more easily break into your system once you've connected it to the Internet. Just kidding. However, whenever you are going to connect something to the "Internet" think hard and multiple times which wholes you are unwillingly opening, especially when it comes to industrial devices. Asking someone on the Internet about how to securely connects your gas turbine to the hostile Internet is a good recipe to become liable(!) in case of any mishaps and accidents that might happen. Remember that there are human lives at stake. So you do not only have to enable connectivity, but you need to harden the Raspbian system. This requires much effort. If you don't do it, you're liable. If you do it wrong, you're liable too.

Putting that aside now; let's first understand what your current network "island" looks like. So, when you plug in your PC into the turbine, what exactly are you doing? Do you directly plug in the Ethernet cable into the turbine and your PC? Or is there some kind of infrastructure with a switch and an DHCPv4 server? What does ipconfig say on your PC side?

And how do you navigateto the Web page of your turbine? Do you need to use an IPv4 address, or can you type in some name into the browser's address bar?
From ZX81 to Raspberry Pi, but wait ... where's the 7805 gone?

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