I wish to to assign the IP from my eth1:2 to a VM; I also have no use of this IP for the host, it would be desirable to be exclusive to the VM.

I've ended up with a setup just like this (eth1:1, eth1:2, etc):
Xen, bridge and multiple IPs on CentOS

And I want to route each IP to a bridge: https://pve.proxmox.com/wiki/Network_Model#Routed_Configuration

I removed my eth1:2 and copied the settings to vmbr1, but it when I attempt to install a guest using that bridge the network is unreachable from the guest.

What should be changed here:

auto vmbr1
iface vmbr1 inet static
address ***from eth1:2***
netmask ***from eth1:2***
bridge_ports eth1
bridge_stp off
bridge_fd 0

If someone could also point me to resources explaining scenarios and why, that would be helpful.


  • Please copy the output of brctl show while the VM is running and copy the vif section of the Xen config file for the VM. The output of ip addr could potentially be useful too. The VM's virtual network interface might not be getting introduced into the bridge. – Celada Nov 20 '14 at 1:54
  • I have yet to install a VM. Particularly with Ubuntu the automated network either fails or there is no network connection available. If you have an image you'd suggest using to debug issues, let me know. – Shawn Khameneh Nov 20 '14 at 15:42
  • I reached out to customer support from my hosting provider; they have explained I must use a portable IP block for this and my statically routed IP's will not work for my needs. I will update later with results. – Shawn Khameneh Nov 20 '14 at 15:53
  • If your eth1:2 already has the address the VM is to have then you can only forward traffic using IP forward. You may want to give the bridge a connection to the VM endpoint, assign a MAC address and then let the VM (from within itself) request the IP address. – Ned64 Mar 14 at 7:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.