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Re: [Xen-users] Network Interface Problems for DomU Firewall

On Wed, Jul 29, 2009 at 5:24 AM, Thomas
Jensen<tom.jensen@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> I changed the DomU configuration file to use the vif=[''] line.

Actually I don't recommend using empty vif line, as it would assign
MAC address dynamically on every boot. You should give it a static

> The DomU
> started fine.  I checked the results of ifconfig after the initial boot and
> the interfaces were still opposite of what they should be (i.e. eth1 should
> be eth0, eth0 should be eth1).

This would be domU OS issue, not Xen issue. On RHEL/Centos I can have
something like HWADDR on /etc/sysconfig/network-scripts/ifcfg-eth0 to
bind a device name (eth0, eth1) to a NIC with a particular MAC. Not
sure how to do it on Lenny though.

> When I tried the command 'ip link set eth1 name eth0', I get the result
> 'RTNETLINK answers: File exists'.

Probably because there's still another link called eth0 :) Try
renaming eth0 to eth-tmp (or something), then rename eth1 to eth0, and
eth-tmp to eth1.

> I found that I can define vifname
> which appears to address my intention of defining the interface name.  So I
> tried adding the syntax so that my DomU config file had the following line
> with the exception of the sanitized MAC address:
> vif = [ 'mac=00:16:XX:XX:XX:XX,vifname=eth1,bridge=eth1' ]
> When trying to boot the DomU with the configuration, I received the
> following error:
> Error: Device 0 (vif) could not be connected. Hotplug scripts not working.

That won't do you what you want. vifname is the name of the interface
on dom0 (the one that's usually called vifx.y). So (for example)
instead of vif1.0 you can have fw-eth0. Note that it's on dom0, not on
domU. In your case it don't work because there's already another
interface on dom0 called eth1.

> Can someone share what syntax combination or steps I need to follow in order
> to obtain a DomU with three interfaces; one of which is "real" as a result
> of PCI pass through and two which are virtual interfaces?

Give the virtual interfaces static MAC, and lookup Debian's
documentation on how to assign a static name to a specific MAC.
On a side note, I believe you could also dump PCI passthrough, and
simply create another bridge on dom0, using that physical interface,
with no IP address (at least this works on RHEL and Ubuntu). That way
all interfaces will be virtual (vif), and you can adjust which one is
listed first on domU config.


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