First you need a device to ping.
NAT is not used in this fashion.
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I feel compelled to “add to my previous post” that NAT cannot be applied to my example either, which refers instead to internal firewall traffic.
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That was a contrived example, sorry. The real problem I wanted to solve was to allow people on the one subnet (blue) to discover a IPP printer on green, and then have print traffic sent to it once it has been discovered. I think my concept of the solution, a phantom printer IP on the blue they users could , was completely wrong.
Okay. Maybe then my example is valid 
.
By default you should not be able to access from BLUE to green.
Whereas you should be able to access from Green to Blue.
These are the default rules on how IPFire handles internal traffic. So, in your case, you need to create an internal traffic rule pe “open a gap” between the BLUE network and the GREEN IP of your printer. I have already experimented with this. I can send you a screenshot of my rule…
I rewrote it. I had personalized it too much. This should be the easiest way. I hope he said it right.
That question seems to have already been asked by yourself in another post https://community.ipfire.org/t/printer-discover-traffic/10309 and appeared to have been solved with the use of the mDNS Repeater addon based on your last reply in that thread.
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yes, you are 100% correct. Routing typically refers to the process of forwarding packets from one network to another, which is a Layer 3 (Network layer) operation, handled by routers. In a single subnet, we usually talk about “switching”. Communication within the same subnet is primarily a Layer 2 job handled by switches, which use MAC addresses to forward frames to the correct destination.
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@cfusco , I sincerely thank you for the confirmation. Just think that I have come to think this way with practical tests done with IPFire itself over the past few years. I am enjoying this simple and powerful firewall more and more and it allows me to learn and experiment with many things at the network level.
Forgive my drawings. Maybe there is free software suitable for making these patterns?
@casabenedetti , just fundamental thought from an old informatics guy.
Learning new things ( in your case networking/firewalling/… ) should be done not only by experimenting with products in this ‘new world’. It is necessary to learn the basics from literature.
Reasons:
- every product contains errors, it isn’t desirable to take these as ‘feature’; especially because these bugs are not easily recognisable, otherwise they would have been corrected.
- literature usually describes the topic in general, not based on a single SW product.
- ( asking questions based on knowledge in the thematical field doesn’t bind working effort of devs and mods more than necessary )
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your drawings are clear. That’s what matters.
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Yes, I acknowledge the above to be true. And before I do that, I think I will also have to study English well. I see on the net that these topics are covered in English. Very often I struggle to understand them. And so I am forced to resort to proof. As a result, I always have doubts whether what I understand is true or not.
you are doing both at the same time. That is the best way to go. ChatGPT 3.5 is quite good at translating to and from English. By observing how the model does it, you will absorb more than you realize, and learn. Keep going. You will be amazed how far you will progress if you keep trying.
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Yes. I am already experimenting with ChatGPT 3.5 as you suggested in a private message. Really amazing. I will also use it for English .
I cannot agree more.
By the way, in addition to what you have listed, one more reason for learning the hard way is to avoid the risk of creating spurious correlation between two events that have nothing to do with each other.
Personal case point, where I associated two things that had nothing to do with each other.
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Perhaps this applies to all disciplines: a good culture, then you put what you learn into practice.
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Yes. I read. I am also of the opinion that to err is human.
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more than that. Error correction is how we (and also AI) learn. Think how a child learns to walk. Making mistakes is the foundation of human knowledge. Error-correction does not work only when we let our intrinsic need to protect our self-image to interfere. Our ego is sometimes the worst enemy we have.
EDIT: after I understood how the LLMs learn to answer questions, I realized that there is nothing intelligent about it. Yet, the world is full of people that are inferior to AI because their ego makes them a worst learner than a stupid language model. I find this depressing.
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I think ChatGPT’s mistakes are also man-made. Does ChatGPT not learn from us? If so it also learns from our mistakes.
in a way. You give human sentences as a training set. You have an algorithm that removes words from this set. The model try to guess which word was removed. Then it checks the accuracy of the prediction, changes some parameters and try again until it reaches a decent level of accuracy. The error and the error correction are generated by the algorithm.
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I think this thread is going massively OT.
Is the original problem solved by learning the network basics?
BTW: even networking is a kind of formal discipline, like mathematics and informatics. Have you tried asking ChatGPT questions of these areas? The learning model isn’t good for these.