Can we run guest OS without using NAT and iptables?

Can we run guest OS without using NAT and iptables?

[freak 62]

 Can we run guest o.s. on KVM without enabling NAT and iptables?

    The reason to do this is , I wanted to disable conntrack module
from my system and to disable that I must have to delete iptable and
NAT.

     I am getting the following message, when I start guest o.s. on
KVM (iptable and NAT disabled):

        Error starting domain: internal error 'Network default' is not active.

     Is their any way to run guest o.s. with NAT disabled? or Is their
any way to disable conntrack module and still can use KVM to run guest
OS ?

   I am using Ubuntu 10.04

    Any help?

Re: Can we run guest OS without using NAT and iptables?

[Stefan Hajnoczi]

On Mon, Oct 29, 2012 at 12:55:43PM +0530, freak 62 wrote:
>  Can we run guest o.s. on KVM without enabling NAT and iptables?
> 
>     The reason to do this is , I wanted to disable conntrack module
> from my system and to disable that I must have to delete iptable and
> NAT.
> 
>      I am getting the following message, when I start guest o.s. on
> KVM (iptable and NAT disabled):
> 
>         Error starting domain: internal error 'Network default' is not active.
> 
>      Is their any way to run guest o.s. with NAT disabled? or Is their
> any way to disable conntrack module and still can use KVM to run guest
> OS ?
> 
>    I am using Ubuntu 10.04

This is a libvirt question since libvirt sets up the networking
configuration.  You can try a different network config either using the
virt-manager GUI tool or by editing the network XML, which is documented
here:

http://libvirt.org/formatnetwork.html

CCed libvirt mailing list.

Stefan

Re: Can we run guest OS without using NAT and iptables?

[Cole Robinson]

On 10/29/2012 05:30 AM, Stefan Hajnoczi wrote:
> On Mon, Oct 29, 2012 at 12:55:43PM +0530, freak 62 wrote:
>>  Can we run guest o.s. on KVM without enabling NAT and iptables?
>>
>>     The reason to do this is , I wanted to disable conntrack module
>> from my system and to disable that I must have to delete iptable and
>> NAT.
>>
>>      I am getting the following message, when I start guest o.s. on
>> KVM (iptable and NAT disabled):
>>
>>         Error starting domain: internal error 'Network default' is not active.
>>
>>      Is their any way to run guest o.s. with NAT disabled? or Is their
>> any way to disable conntrack module and still can use KVM to run guest
>> OS ?
>>
>>    I am using Ubuntu 10.04

You can remove the default virsh network like

sudo virsh net-destroy default
sudo virsh net-undefine default

The most common networking setup that doesn't use NAT + iptables is probably
bridged networking:

http://wiki.libvirt.org/page/Networking#Bridged_networking_.28aka_.22shared_physical_device.22.29

- Cole