Send json tcp request

General
1

Hello all,

I'm trying to get data from my 3d printer through tcp port 35. I was able to sniff the packages between my computer and the printer with wireshark, but I was not able to get data with node red. It seems that there is a communication with custom json. I've tried to inject the json data directly through the tcp request node but I got a connection error.

I've attached some pictures of the wireshark dump because I am not able to upload the dump as zip file.

host-printer_1
host-printer_1.JPG974×318 53.1 KB
host-printer_2
host-printer_2.JPG969×440 92.9 KB

There are 3 packages sent repeatedly:

  1. from the host to the printer with a length of 54 bytes
  2. from the host to the printer with a length of 183 bytes including the json data
  3. from the printer to the host with a length of 775 bytes with the result

Is there anyone who is familiar with wireshark who can help me here?

Thanks in advance
Kay

2

printer_host_result
printer_host_result.JPG942×973 225 KB

3

you need to check that you can connect to port 35 - quite often ports below 1024 are only available to root by default.

4

Yes, you are right. Thanks for pointing. I will check that.

Kay