Hello,

sorry for the noise, but I'm starting with openVZ and have some trouble 
setting up things.

I plan to virtualize a server which hosts (among other network services) 
a dhcpd server. As stated from various docs, I need to setup a veth 
device to account for dhcpd broadcasts. But this server should also have 
an IPv6 address due to other services which are not easily moveable to 
another VS due to publicly-known IP address and name constraints.

I'm working on Debian Etch with debian-systs packages: vzctl 
3.0.22-1dso1, fzakernel-2.6.18-686 028stab051.1.

For now I got an IPv4 veth working, loosely inspired from 
http://wiki.openvz.org/Veth :

- enabled IPv4 forwarding and proxy_arp on hardware node for both 
physical interface (ethX) and virtual one (vethXXX.0)
- configured virtual eth0 by manually editing /etc/network/interfaces 
file in VS tree
- added routes to vethXXX.0 on hardware node at VS startup with 
vznetaddroute script and VETH_IP_ADDRESS in /etc/vz/conf/XXX.conf.

In this manner, all IPv4 pings work correctly (I didn't yet tested with 
a real dhcpd however).
But for IPv6, virtual server and hardware node can't even ping eachother !

Activating IPv6 forwarding doesn't seem to help, and has the annoying 
side effect to switch devices in "router" mode, disabling router 
sollicitations and default route and prefix advertisement acceptance.

I also read various docs about veth and IPv6, some of them implying 
bridging: 
http://forum.openvz.org/index.php?t=msg&goto=14622&&srch=veth+IPv6#msg_14622.

Questions :

- is veth with IPv6 really supported ?
- which is the correct way to setup a veth with IPv4 and IPv6 ?
- is bridging required ?
- anyway, is veth the correct way to run a dhcpd server in a VS ? on 
http://forum.openvz.org/index.php?t=msg&goto=14982&&srch=dhcpd#msg_14982 
it seems necessary to setup a dhcp relay on hardware node...

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On 24 January 2008 13:38:13 Benoit Branciard wrote:
> Hello,
>
> sorry for the noise, but I'm starting with openVZ and have some trouble
> setting up things.
>
> I plan to virtualize a server which hosts (among other network services)
> a dhcpd server. As stated from various docs, I need to setup a veth
> device to account for dhcpd broadcasts. But this server should also have
> an IPv6 address due to other services which are not easily moveable to
> another VS due to publicly-known IP address and name constraints.
>
> I'm working on Debian Etch with debian-systs packages: vzctl
> 3.0.22-1dso1, fzakernel-2.6.18-686 028stab051.1.
>
> For now I got an IPv4 veth working, loosely inspired from
> http://wiki.openvz.org/Veth :
>
> - enabled IPv4 forwarding and proxy_arp on hardware node for both
> physical interface (ethX) and virtual one (vethXXX.0)
> - configured virtual eth0 by manually editing /etc/network/interfaces
> file in VS tree
> - added routes to vethXXX.0 on hardware node at VS startup with
> vznetaddroute script and VETH_IP_ADDRESS in /etc/vz/conf/XXX.conf.
>
> In this manner, all IPv4 pings work correctly (I didn't yet tested with
> a real dhcpd however).
> But for IPv6, virtual server and hardware node can't even ping eachother !
>
> Activating IPv6 forwarding doesn't seem to help, and has the annoying
> side effect to switch devices in "router" mode, disabling router
> sollicitations and default route and prefix advertisement acceptance.
>
> I also read various docs about veth and IPv6, some of them implying
> bridging:
> http://forum.openvz.org/index.php?t=msg&goto=14622&&srch=veth+IPv6#msg_1462
>2.
>
> Questions :
>
> - is veth with IPv6 really supported ?

Yes, it is supported.

> - which is the correct way to setup a veth with IPv4 and IPv6 ?
> - is bridging required ?

Using veth with bridge is preferable. If you don't want use veth + bridge try 
to play with venet . You can setup IPv4, IPv6 in any order.

> - anyway, is veth the correct way to run a dhcpd server in a VS ? on
> http://forum.openvz.org/index.php?t=msg&goto=14982&&srch=dhcpd#msg_14982
> it seems necessary to setup a dhcp relay on hardware node...

veth allows passing network broadcast traffic to VPS, also don't mind about IP 
address in VPS. veth was designed for with cases.

Please read with article: 
http://wiki.openvz.org/Differences_between_venet_and_veth


-- 
Thanks,
Vitaliy Gusev