On Fri, 8 May 2009 19:08:06 -0600 Daniel Robbins <drobbins@xxxxxxxxxx> wrote: > Your code in 2.6.27 works perfectly. > > Let me tell you what I was doing wrong, and if you could tell me why > it didn't work, I'd really appreciate it :) (Might also be a good > addition to the Net:Bridge FAQ): > > # brctl addbr br0 > # brctl addif br0 eth0 > # ifconfig br0 10.0.1.220 netmask 255.255.255.0 > # brctl addif br0 veth100.0 > # brctl addif br0 veth102.0 > > Now, the zinger: > > # ifconfig br0 hw ether "12:34:56:78:90:ab" > > ^^ By using a unique MAC address, this command totally disables my > bridge, and the machine can no longer send or receive data. > > If I use a MAC that is already in use by my bridge's sub-interfaces, > however, (ie. from eth0, veth100.0 or veth102.0) then there's no > problem, and everything works, and the MAC address is sticky as it > should be. > > So this was the mistake I was making - I was using a user-generated > MAC for my testing rather than choosing a MAC from one of the bridge's > interfaces. > > So, my question is: why doesn't a user-generated MAC work? On the > surface, it seems like all devices on the same LAN should have > different MAC addresses. Yet, with Linux bridging, it appears that (at > least in certain conditions, like if there is an IP assigned to the > bridge,) then the bridge *must* share a MAC with one of its > sub-interfaces in order to function properly. This is very > counter-intuitive and a mystery to me and probably quite a few other > bridging newbies (which is why an explanation would make a great > addition to the Net:Bridge FAQ :) The problem is that the bridge only thinks a packet is "local" if it arrives with destination hw addr == incoming device address. _______________________________________________ Bridge mailing list Bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/bridge
