KVM bridged network blocks VM to VM traffic

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http://forums.fedoraforum.org – Hello, I'm using KVM on Fedora 12 x86_64 to run several virtual machines. I've set up a bridged network interface, as I need these virtual machines to co-mingle on the same network as the physical machines. The bridge is setup as per the scripts below. I'm using the default F12 sysctl.conf. The problem is this... although virtual machines CAN access other machines on the network, including the Internet, virtual machines CANNOT communicate with each other. No pings, no file sharing, etc. I don't know why these VM's are unable to communicate with each other. I would appreciate any ideas or suggestions! Thanks!! br0 interface: Code: # cat /etc/sysconfig/network-scripts/ifcfg-br0 DEVICE=br0 TYPE=Bridge BOOTPROTO=dhcp ONBOOT=yes DELAY=0 eth0 interface Code: # cat /etc/sysconfig/network-scripts/ifcfg-eth0 # Intel Corporation 82573L Gigabit Ethernet Controller DEVICE=eth0 HWADDR=00:19:D1:31:E9:E3 ONBOOT=yes TYPE=Ethernet #BOOTPROTO=dhcp NAME="System eth0" UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 PEERDNS=yes PEERROUTES=yes BRIDGE=br0 MTU=9000 sysctl.conf Code: # cat /etc/sysctl.conf # Kernel sysctl configuration file for Red Hat Linux # # For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and # sysctl.conf(5) for more details. # Controls IP packet forwarding net.ipv4.ip_forward = 0 # Controls source route verification net.ipv4.conf.default.rp_filter = 1 # Do not accept source routing net.ipv4.conf.default.accept_source_route = 0 # Controls the System Request debugging functionality of the kernel kernel.sysrq = 0 # Controls whether core dumps will append the PID to the core filename. # Useful for debugging multi-threaded applications. kernel.core_uses_pid = 1 # Disable netfilter on bridges. net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-arptables = 0 brctl show Code: # brctl show bridge name        bridge id                STP enabled        interfaces br0                8000.0019d131e9e3        no                eth0                                                         vnet0                                                         vnet1 virbr0                8000.000000000000        yes ---------- Post added at 10:53 AM CST ---------- Previous post was at 10:11 AM CST ---------- One more piece of info here... the bridge does see the virtual machines's MAC addresses: Code: # brctl showmacs br0 port no        mac addr                is local?        ageing timer   1        00:0f:b5:23:73:05        no                194.94   1        00:15:af:75:9d:bb        no                209.88   1        00:19:d1:31:e9:e3        yes                  0.00   1        00:22:6b:5f:1f:3d        no                  0.01   1        00:23:32:c9:e9:f8        no                159.23   1        00:30:18:a9:b2:76        no                  0.00   2        32:d2:69:48:a6:64        yes                  0.00   2        52:54:00:07:ca:6b        no                159.30   3        52:54:00:6f:7a:12        no                208.36   3        f6:ac:62:68:f5:8b        yes                  0.00 The bold entries correspond to the virtual machine's addresses. ---------- Post added at 11:40 AM CST ---------- Previous post was at 10:53 AM CST ---------- Although this certainly may be a case of user error, I'm not positive that this is not a bug. Therefore: https://bugzilla.redhat.com/show_bug.cgi?id=542405 Of course, if anyone does have ideas, please do let me know! (HowTos)