/etc/init.d/networking needs to be restarted

[compdoc]

You can see that br0 and eth0 have the same MAC address, and so br0 is a
bridge that the kvm guests can use to reach the lan. You should be able to
use the bridge as well, although I don't do it that way. I always use a
bridge with a 2nd, separate ethernet card that the guests use to themsleves.

The mask is an odd number, but maybe you have set it that way for a reason.