We are having a server with good CPU and RAM,so we are planning to do XEN virtualization on ubuntu 12.04 server to handle high traffic. The plan is to keep the host machine only to manage VMs(no NAT ing).

A New public IP will be assigned to that VM,For that i think we need a Bridge to external network(Since my Machine has only single ethernet card aliased with 4 different Pub IP's) Is it possible to create a bridge using aliased IP

single ethernet card aliased to 4 pub IPs

Do we need an additional Ethernet card to do Bridging.Only have ssh access to the machine. Any suggestions will be appreciated.

  • Why would you need an aliased IP? If the network is running in bridge mode the public IP sits on the virtual machine's network interface, not on the host machine.
    – James Yale
    Commented Jun 7, 2012 at 13:28

2 Answers 2


You don't need to alias. You create a bridge out of your physical network controller and then assign the server's IP data to that bridge. Xen then makes virtual interfaces on that same bridge and the domU's will actually give them an IP (but that is not visible inside the dom0).

Xen has scripts for all this.

You might want to read this.

Also, I wrote a short manual (mostly for my own reference) here. Read it, but take it with a grain of salt, it could be outdated. And, it's Debian. Ubuntu didn't used to have the Xen Hypervisor. I see they do now, but I don't know if installing is the same on Ubuntu and Debian.


You do not need an additional ethernet card.

You can follow the instructions here: https://help.ubuntu.com/community/XenProposed#Network_Configuration

The configuration that you describe is the probably the most common way to use Xen (bridged networking).

The Xen wiki page referenced above is out of date, the updated general Xen.org wiki page for networking in Xen 4.1+ is:


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