Hello list, I'm setting up a virtual network consisting of several UMLs (User Mode Linux) connected with the virtual bridge. Communications works quite well between the host and the virtual machines. Setup: 2 UMLs connected via tap-devices to the bridge (tap1,tap2). The host uses the bridge-device br0 to talk to the clients. Now I want to tcpdump the traffic between host and UML1 on virtual machine UML2. With the standard-settings UML2 only catches the initial ARP-broadcasts (but that's the intended behaviour of the bridge/switch). :-) Now I set "brctl setageingtime br0 0", so that the bridge behaves like a hub (it forgets the MAC-addresses immediately) and broadcasts all packets on all connected ports. Checking this with "brctl showmacs br0" shows, that this is working, the MAC-table is always empty. BUT: on UML2 (the listening machine) I see only the complete traffic coming from the host (via br0 into the bridge), but the answers from UML2 to the host (entering the bridge on tap2) are hidden (only broadcasts can be seen). Why does the broadcasting of all packets only work from the bridge directly (br0) and not from the connected tap-devices? Could this have to do with the fact, that with version 1.0.4 of the bridge-utils (Debian 3.1, testing) I can't control the GC-time of the bridge? In the mailing-list archive I found a thread, where someone wanted the bridge to be configured as a hub, but the advice to remove some lines of code from the bridge-code didn't work for me, the bridge is unusable after removing the code. Can someone give me a hint, how to get the desired behaviour? An option for switching between hub- and switch-behaviour would be nice... ;-) thanx in advance, Harald Sauff
