> /kernel: arp: unknown hardware address format (0x4d6f)

It appears that there is some NIC ("network card") somewhere in the network
which transmits a MAC address in a format which makes no sense to the OS.

Effects of reception of such a "unknown hardware address format" can range
from "nothing happens" to "network traffic stops".

The cause may be a hardware problem, a NIC which has been tampered with, a
Linux box with a buggy driver, whatever.

Try to disconnect you local boxes one by one and try to find out if one of
them causes the problem.

Don't remeber if you can add permanent entries into the arp table on the
m0n0box; this might help if one of the local boxes is faulty.

Good luck!

Best regards, KLaus
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