Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Un recognized node in my network


Not sure if this is the right place to ask this but here goes....


I have a DPC3939 Wireless Gateway, supplied by Comcast. When Inspecting the LAN for problems I discovered a node at, which I can ping, but otherwise not contact. This node also has the strange MAC address of 00:05:04:03:02:01.

In several other forums (one being Comcast's) I have asked about this, but Comcast has no answer. others have discovered this same node either at or, depending on what local address you have implemented, with exactly the same MAC address

This node exists, if I completely remove the Gateway from any connection, and scan it with my smartphone using an app called Fing.

So I was wondering if Cisco as the manufacturer of the device might have some insight, even though I realize that the firmware in the device belongs to Comcast. Is there an Internal device that is meant to support VOIP or Home Security that might show up in this manner???  Is this some sort of security being implemented by Comcast??


Thanks for your time,

Mike Webb

VIP Gold

You are true, the firmware is

You are true, the firmware is Comcast's. I'm almost sure Cisco will not comment features of their firmware. Especially if Comcast is not willing to respond you ...

Related: Cisco Consumer Set-Tops, Modems and Gateways