Hi everyone. I can't for the life of me get bonding and bridging to work for the KVM setup I'm building. I'm using a fresh install (not an upgrade) of Ubuntu Server 10.10. I have 4 NICs on the same subnet (two intended for each of my two VMs). I'm trying to achieve the setup that Uthark describes here. But following his guidelines didn't work for me. My eth0 and eth1 did not come up, and "brctl show" showed that br0 didn't have any interfaces (the bond). I assumed it didn't work because he's using 10.4, and this article says there's a recent change in bonding: [I can't post more than one hyperlink per post because I'm a newbie.] I had to use this article to get my interfaces to work at all on the same subnet, which is why I have the post-up lines on some of my interfaces: [I can't post more than one hyperlink per post because I'm a newbie.] I installed ifenslave and ethtool. I also created /etc/modprobe.d/aliases.conf with the following content: alias bond0 bonding options bonding mode=6 miimon=100 downdelay=200 updelay=200 And I included "bonding" in /etc/modules So, after several approaches, here is my latest interfaces file: auto lo iface lo inet loopback auto eth5 iface eth5 inet manual auto br5 iface br5 inet static post-up /sbin/ip rule add from [network].79 lookup 10 post-up /sbin/ip route add table 10 default via [network].1 src [network].79 dev br5 address [network].79 netmask 255.255.255.0 network [network].0 broadcast [network].255 gateway [network].1 bridge_ports eth5 bridge_stp off bridge_fd 0 bridge_maxwait 0 auto eth2 iface eth2 inet manual auto br2 iface br2 inet static post-up /sbin/ip rule add from [network].78 lookup 11 post-up /sbin/ip route add table 11 default via [network].1 src [network].78 dev br2 address [network].78 netmask 255.255.255.0 network [network].0 broadcast [network].255 gateway [network].1 bridge_ports eth2 bridge_stp off bridge_fd 0 bridge_maxwait 0 iface eth0 inet manual iface eth1 inet manual auto bond0 iface bond0 inet static bond_miimon 100 bond_mode balance-alb up /sbin/ifenslave bond0 eth0 eth1 down /sbin/ifenslave -d bond0 eth0 eth1 auto br0 iface br0 inet static address [network].60 netmask 255.255.255.0 network [network].0 broadcast [network].255 gateway [network].1 bridge_ports bond0 eth2, eth5, br2, and br5 all seem to be working fine. The only other thing I could find that looked suspicious is an error regarding bonding in /var/log/messages: kernel: [ 3.828684] bonding: Warning: either miimon or arp_interval and arp_ip_target module parameters must be specified, otherwise bonding will not detect link failures! see bonding.txt for details. even though there is a bond-miimon line in /etc/network/interfaces (if that's what they're talking about). Also, the bond seems to go in and out of promiscuous mode several times on boot: Jan 20 14:19:02 kvmhost kernel: [ 3.902378] device bond0 entered promiscuous mode Jan 20 14:19:02 kvmhost kernel: [ 3.902390] device bond0 left promiscuous mode Jan 20 14:19:02 kvmhost kernel: [ 3.902393] device bond0 entered promiscuous mode Jan 20 14:19:02 kvmhost kernel: [ 3.902397] device bond0 left promiscuous mode Jan 20 14:19:03 kvmhost kernel: [ 4.998990] device bond0 entered promiscuous mode Jan 20 14:19:03 kvmhost kernel: [ 4.999005] device bond0 left promiscuous mode Jan 20 14:19:03 kvmhost kernel: [ 4.999008] device bond0 entered promiscuous mode Jan 20 14:19:03 kvmhost kernel: [ 4.999012] device bond0 left promiscuous mode Any advice would be greatly appreciated. It seems that this must be possible, based on other posts, but I can't see what I'm doing wrong. Thanks.