Re: Forced lladdr change with bridge - or not?

[Pascal Hambourg <pascal.mail@plouf.fr.eu.org>]

Pascal Hambourg a écrit :
> bdschuym@telenet.be a écrit :
> 
>> Apparently you can get around this problem, see (I didn't verify):
>> http://backreference.org/2010/07/28/linux-bridge-mac-addresses-and-dynamic-ports/
> 
> "if the bridge's MAC address is forced to a specific value, the bridge
> "remembers" that and makes the address permanent. But there's a caveat:
> the address must belong to one of the devices enslaved to the bridge"
> 
> Hmm, I remember I had a similar idea, but it didn't work : the address
> was not permanent and could still be replaced if an interface with a
> lower MAC address was added. Maybe I didn't do things right, I will try
> again, thanks.
> 
> I had the idea that maybe it was a kernel change, so looking at the
> kernel changelogs, I found this in ChangeLog-2.6.27 :
> 
>> commit 92c0574f11598c8036f81e27d2e8bdd6eed7d76d
>> Author: Stephen Hemminger <shemminger@vyatta.com>
>> Date:   Tue Jun 17 16:10:06 2008 -0700
>>
>>     bridge: make bridge address settings sticky
>>
>>     Normally, the bridge just chooses the smallest mac address as the
>>     bridge id and mac address of bridge device. But if the administrator
>>     has explictly set the interface address then don't change it.
> 
> At the time I tried to force a permanent MAC address to the bridge I
> used a kernel older than 2.6.27, this explains why it didn't work.

I tried again. Indeed it worked with 2.6.27 but not with 2.6.26, as
expected. Contrary to the article, I observed that the statically
assigned MAC address can be arbitrary and does not have to belong to one
of the enslaved devices.