• Registered: 2008-01-21
  • Posts: 3

Topic: Duplicate MAC address

OK, I thought this wasn't supposed to happen, but the MAC address of my Chumby matches the MAC address of my network printer. So DHCP will give me the IP of the Printer, and of course, unless I manually set the IP, nobody can print any more.

First, I though MAC address had blocks assigned to hardware manufacturers, so unless Chumby is an HP product, there is no way they should have the same MAC address.

Second, I can't make a DHCP reservation for my Chumby, because of the conflicting MAC address. I can manually set the IP on the Chumby, but I can't tell DHCP to never give out the IP address, so potentially another device can attach to the network and get the same IP handed to it.

Is there a way to permanently (or at least semi-permanently) change the MAC address?

  • Duane
  • Duane
  • Blue Octy
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  • From: San Diego, CA
  • Registered: 2006-08-24
  • Posts: 8,197

Re: Duplicate MAC address

Not sure how this is possible.

We don't assign the MAC address - it's on the wifi dongle, which is an off-the-shelf product we purchase in bulk.

Can you please list the MAC addresses you're seeing for both the chumby and your printer?

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  • mdkail
  • Administrator
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  • From: san diego
  • Registered: 2007-08-11
  • Posts: 146

Re: Duplicate MAC address

can you also post your network configuration?  such as, perhaps are you using DD-WRT's ``client bridge'' mode?

also, please post the output of ``arp -a''

thanks
/mdkail

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  • Duane
  • Duane
  • Blue Octy
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  • From: San Diego, CA
  • Registered: 2006-08-24
  • Posts: 8,197

Re: Duplicate MAC address

More info - the MAC address of all chumbys shipped to date should start with the OUI of '00:12:0E', which is assigned to AboCom, which is the upstream manufacturer of the part we're using.

Here is a full list of assigned OUIs.

Duane's Website

  • Registered: 2008-01-21
  • Posts: 3

Re: Duplicate MAC address

The MAC address in question is 00:12:0e:6f:d0:56, so the Color LaserJet is definitely assigned the same group as the wifi module. I didn't see any way to modify the printer's MAC address, I've only seen that in routers anyways. It's actually looking like it's more the printer's fault than the Chumby. I did a printer configuration printout, and I have two numbers, the hardware address is 00143848bdb8, and then I have and ARP Duplicate IP Address with the 00:12:0e:6f:d0:55. I looked up the OUI group, and HP is supposed to be at 00-14-38, which is what the hardware address is set at. So I'm not sure about the ARP duplicate message.

  • Duane
  • Duane
  • Blue Octy
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  • From: San Diego, CA
  • Registered: 2006-08-24
  • Posts: 8,197

Re: Duplicate MAC address

Not sure what to tell you  - as far as I know, the wifi module in the chumby is not capable of setting the MAC address.

I'm still suspicious of your network somehow - the odds of *you* receiving a chumby having the same MAC address of a mis-addressed HP printer you also own seem so astronomical to make me a bit skeptical that that's actually what's going on here.

If you remove the chumby from the network entirely, and restart the various other devices, does a query for the 00:12:0e MAC still show the printer?

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  • mdkail
  • Administrator
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  • From: san diego
  • Registered: 2007-08-11
  • Posts: 146

Re: Duplicate MAC address

i'm willing to try and help you debug this, but need to know a bit more detail about your overall network configuration, including
what devices you are using.

/mdkail

mdkail's Website