I've been inspired by the board to investigate alternate ideas, particularly based on the feedback about Soekris reliability. I had always considered the devices to be highly reliable, but am now seeing quite a few issues, particularly around the thermal package. I have the device in a large closet on a high shelf, which should be OK, but got me to dig. Well, it appears that the stock case and heat sink are NOT up to the job, as the CPU core is currently running around 79C with little / no load.
I now expect the printer IS causing the issue, due to heating the closet, not some strange broadcast packets!!!
Incidentally, does anyone know how to override the Tj Max setting - the coretemp module is unable to read the CPU ID and sets the Tj Max to 100; for the net6501-50 it should be 90.
Tom