Hi Mike I am a longtime comcast customer that is also having the same problem. However the unknown node with MAC address 00:05:04:03:02:01 shows on 10.0.0.254 since I never changed the default address on my DPC3939. I can also ping it but cannot access it. I had comcast switch out the gateway since beside the unknown node, the gateway default address changes from 10.0.0.1 to 172.16.12.1 occasionally on its own. The change in default address never last for long and started in October. Gateway support cannot explain either problem and the tech that brought out the new gateway blamed my computer. He said that since the problem is with my wired connection, it had to my computer since that connection could not be hacked. Have you spoken to anyone at Comcast about it? Di
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