Re: [Xen-users] peth0: received packet with own address as source address

[Matthew Haas <haas@xxxxxxxxxxxxxx>]

Dylan Martin wrote:
> Just a dumb idea: are you sure the two boxes have different mac
> addresses?
 Yes, eth0 on both machines have unique MAC addresses.

> Slightly less dumb idea: grep through /etc looking for your IP
> address and MAC address.  Maybe the system is consulting some dumb
> file and getting the wrong address that way.  
 One of the first things I did (just for IP), and I just did it again 
looking for MAC address (upper and lowercase)... still came up empty.
> Much less dumb idea: start up tcpdump on both machines and see
> what actual traffic is causing the error.
 I see the following when running tcpdump on peth0 from machine B (the 
duplicated one-- machine A is the original):
18:33:58.091906 fe:ff:ff:ff:ff:ff (oui Unknown) > Broadcast, ethertype 
Unknown (0x88a2), length 60:
        0x0000:  1000 ffff ff01 0000 0000 0000 0000 0000
        0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
        0x0020:  0000 0000 0000 0000 0000 0000 0000
18:33:58.091907 fe:ff:ff:ff:ff:ff (oui Unknown) > Broadcast, ethertype 
Unknown (0x88a2), length 60:
        0x0000:  1000 ffff ff01 0000 0000 0000 0000 0000
        0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
        0x0020:  0000 0000 0000 0000 0000 0000 0000
18:33:58.091908 MM:AA:CC:HI:NE:BB (oui Unknown) > Broadcast, ethertype 
Unknown (0x88a2), length 60:
        0x0000:  1000 ffff ff01 0000 0000 0000 0000 0000
        0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
        0x0020:  0000 0000 0000 0000 0000 0000 0000
18:33:58.122515 fe:ff:ff:ff:ff:ff (oui Unknown) > Broadcast, ethertype 
Unknown (0x88a2), length 60:
        0x0000:  1000 ffff ff01 0000 0000 0000 0000 0000
        0x0010:  0000 0000 0000 0000 0000 0000 0000 0000
        0x0020:  0000 0000 0000 0000 0000 0000 0000

 I occasionally see the other machine's MAC pop up as well. Running 
tcpdump on Machine A yields the same looking output.
FE:FF:FF:FF:FF:FF is the MAC assigned to the peth0, vifs, xenbr0s on 
what appears to be all my Xen machines.
 Not sure what to make of it, aside from it is trying to broadcast an 
ethernet frame of unknown type.
 Thanks for the suggestions.

-Matthew
--
 Matthew Haas
 Visiting Instructor
 Corning Community College
 Computer & Information Science
 http://lab46.corning-cc.edu/haas/home/

  "Writing should be like breathing;
   It is one of those important things we do." -- me

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