Hi All, I have two bits of hardware connected to each other via an ethernet cable, they are basically two computerised controllers for a very advanced boiler, lets call them A and B, so A and B are not seeing each other and the vendor has told me to replace the ethernet cable which I have done already, but A and B still do not see each other. To try and deep dive the issue I wanted to know if there is a way or is there any such device that I can plug in between A and B which would allow me to capture the network traffic, if any, between them, please bear in mind that A and B do not have any external monitor connections nor do they allow any interaction with the O/S installed on them, so does anything exist that would allow me to do what I want? So at the moment it is like this ... A -----EthernetCable ----- B And what I want to do is this ... A -----EthernetCable ----- NetworkCaptureDevice -----EthernetCable ----- B I hope that makes sense! :) Thanks Jim asked 30 Nov '15, 07:05  JimBob321 |
2 Answers:
You can use either a switch that will mirror or span ports, an old hub if you can find one, or for $$$ a network tap, or even a machine in the middle. See the Wiki page on Ethernet Capture Setup, and the hub and switch reference pages. answered 30 Nov '15, 07:25  grahamb ♦ |
It does make sense but there may be a difficulty negotiating the link between the devices at L1 - in such case a capturing device would show nothing. I wonder whether the Ethernet interfaces of your hardware could be so old that they would not be able to auto-detect which pair is which (this functionality is often called "auto MDI/MDI-X") and so you would need to connect both of them to a switch (which is supposed to handle that) or use a so-called "crossed cable". Can you state the parameters/make of the Ethernet interfaces of your rocket boilers? If the cable turns out not to be the issue, a PC with two network cards (probably most easily available), or a switch with monitoring capability, or a "tap" would help you capture what happens on the wire once the link is established at L1. answered 30 Nov '15, 07:37  sindy |
