finding the mac address of my 3c10200b boxes

[greg24]

Hi,

I have started using wireshark on my network and have noticed a large amount of spanning tree protocol packets.  spanning tree isn't necessary on the network so I have turned it off at the switches (3Com 4400 units).  The wireshark messages changed as I turned off spanning tree.  The message had x:y:z, I turned spanning tree off on x:y:z and the message changed to another switch.  I kept going until all of the switches had spanning tree turned off.  However I am still getting spanning tree packets from 3Com mac addresses.  These mac address are not telephones or the networking equipment.  I am guessing they are coming from the 2 3C10200Bs I have but I don't know how to find their mac addresses.  These 2 boxes plug into my ethernet network so I am assuming they have mac addresses even if they don't have an IP address.  So how can I find out the mac address of these boxes?

I admit I am guessing at this point as I have pretty much eliminated all of the other equipment.  The mac addresses are 0012a99d53d5 (source) and 0012a99d53c0 (root).  I have even started pulling the plug on different segments to try to locate this equipment and haven't succeed so far.

Thanks,

[bosoxfan]

hi.. only way to know the mac addresses of the phone are to either look on the bottom of the phone.. each phone has a label with the mac address or scroll through the LCD for the mac address.

All 3com phone mac addresses begin with 00e0bb, so those two MAC addresses are not phones.

they do belong to 3Com, so they are probably your switches... or PC has 3com NIC in it.

[greg24]

Thank you for the response.  I have a list of the mac addresses for the phones from NBX.  I need the mac addresses from the big white boxes that hold my analog terminal cards. 

I don't think it is a 3Com NIC as everything is Dell and uses the builtin NIC.  However it is a good suggestion and I will check the boxes to make sure.

Thanks,

[bosoxfan]

The big white boxes that the analog line cards go into do not have a MAC address.. they are used only for power and for connecting to the network..

The two MAC addresses you mention are assigned to 3Com Corp.. so I would check the switches, if no 3com NIC's

Hope this helps!

[merlin215]

That Mac address belongs to 3Com Europe

Is that  European  purchased equipment ?

 0012a99d53d5

[greg24]

The two 3c10200 boxes and the NBX are all plugged into the same ethernet switch.  If the 3c10200b doesn't have a mac address then how does it communicate with the NBX? 

I saw the 3Com Europe when I did the mac address lookup.  I don't know where this equipment is or what it is.  For all I know it could be some specialty piece of equipment shoved into a hole in the attic.  Yes I have found equipment like that and have either removed it or relocated it.  I will segment my network a little more tonight to try to get a general idea of where this equipment is.  I already turned off the voice and data networks to two buildings and the spanning tree message in wireshark didn't change so I know the equipment isn't there.  I still have a few buildings to go.

[bosoxfan · Accepted solution]

How does 3c10200b communicate with the NBX??? the answer is it doesn't.. .no need to.. it is just a chassis to hold the cards... cards communicate with the NBX via the backplane of the chassis....

[greg24]

So the cards in the chasis have the mac addresses.  Doh! 

Thanks for helping me understand this.