RE: Router stops routing after changing MAC Address

["Greg Scott" <GregScott@InfraSupportEtc.com>]

But in a failover scenario you want two devices to have the same IEEE
(station) Address (or MAC Address or hardware address).  So many names
for the same thing!  

When the primary unit fails, you want the backup unit to completely
assume the failed unit's identity - right down to the MAC Address.  The
other way to do it using gratuitous ARPs is not good enough because some
cheap router someplace with an ARP cache of several hours will not
listen and will never update its own ARP cache.  

I like to think of this as bending the rules a little bit, not really
breaking them.  :)

- Greg



>Actually, it doesn't make any difference. Changing the IEEE station
>(physical) address is not an allowed procedure even though hooks are 
>available in many drivers to do this. According to the IEEE 802 
>physical media specification, this 48-bit address must be unique 
>and must be one of a group assigned by IEEE. Failure to follow this 
>simple protocol can (will) cause an entire network to fail. If you 
>don't care, then you certainly don't care about multicast bits either, 
>basically let them set it to all ones as well.

>Cheers,
>Dick Johnson
>Penguin : Linux version 2.6.15.4 on an i686 machine (5589.54 BogoMips).
>Warning : 98.36% of all statistics are fiction, book release in April.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/