Dear Friends, Please find the link to a captured TCP transmission between 2 devices (not from internet). The packets of interst are from a devide at 192.0.0.192 to another devide at 192.0.0.200 . (please filter). The packets of interest beginn after 21:15:30. Each PSH packet has a "Data" Payload, which I am not able to decode (understand). Some of the packets have AASCII data, which makes sense, but most of it makes no sense. I am inclined to believe that the data is not encrypted. The "Data" is encoding for some numbers (scientific numbers). The first person who can decode and explain how the data is organised in the packets will get a reward of 500 USD. Thanks and Regards asked 27 Oct '17, 15:19  guest1 |
One Answer:
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(I'm too busy to work on it right now.) answered 29 Oct '17, 17:33  Guy Harris ♦♦ |
Looks a lot like HP-GL/2.
Dear Friend you may be right. It is indeed an HP machine. Can you help to get it decoded ?
See the Wikipedia page for HP-GL for information about HP-GL and links to HP documents about HP-GL and HP-GL/2.
Note also that one port is port 9100;
/etc/serviceson my machine says:"PDL" probably stands for "Page Description Language", and the page description language in question is probably HP Printer Command Language. As that Wikipedia page says, "HP-GL/2 and PJL are supported by later versions of PCL.", so the data going over the wire is probably some version of HP PCL, with HP-GL/2 included in it.
See also What is port 9100 & How to print to it.