From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 26 Dec 2010 10:31:27 -0800 From: Stephen Hemminger Message-ID: <20101226103127.05cbd1c5@nehalam> In-Reply-To: <4D1779B6.9050305@wanadoo.nl> References: <4D0E868E.4010309@wanadoo.nl> <20101220103754.7d18de50@s6510> <4D0FB6AC.2020901@wanadoo.nl> <4D1779B6.9050305@wanadoo.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Bridge] Why should static MAC address match one of the port MAC addresses - bug? List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Rolf Fokkens Cc: bridge@lists.linux-foundation.org On Sun, 26 Dec 2010 18:21:58 +0100 Rolf Fokkens wrote: > In this particular situation it's not possible to do so as all > interfaces are tap interfaces, with random generated MAC addresses. > Changing the tap interface's MAC address results in this: > > [root@home01 ~]# ifconfig tap0 hw ether BA:B7:73:58:E6:E2 > SIOCSIFHWADDR: Device or resource busy > [root@home01 ~]# > > So that doen't work. I found a trick however: I added a dummy ethernet > interface to the bridge, of which i can specify the MAC address, It > works fine, but in syslog there's the following message: > > Dec 26 17:45:21 home01 kernel: [ 29.316480] br0: new device dummy0 > does not support netpoll (disabling) > > This means that the bridge won't use/support netpoll at all, which may > mean there's an impact on performance. I'm not sure. I can imagine that > a netpoll interface for a dummy interface shouldn't be hard to implement. > The message means you can't use kdump/netconsole/kgdb over that bridge device.