Need help, Getting IPv6 working inside VMs

PrincessOfCats

Hi, I currently have a server with Dacentec. I am currently running VMs behind a VyOS software router.

They gave me a /48 with the network and gateway. The ::1 you see below in the config is the gateway.

Fiddling around, I managed to get IPv6 to work in VyOS with the following config

interfaces {
 ethernet eth0 {
     address <address removed>
     address <address removed>:4CC::2/48
     duplex auto
     firewall {
         in {
             name eth0-v4-FWD
         }
         local {
             name eth0-v4-IN
         }
     }
     smp_affinity auto
     speed auto
 }
 ethernet eth1 {
     address 10.5.0.1/16
     address <address removed>:4CC:babe::1/64
     duplex auto
     firewall {
         local {
             name eth1-v4-IN
         }
     }
     ipv6 {
         router-advert {
             name-server <address removed>:4CC:babe::1
             prefix <address removed>:4CC:babe::/64 {
             }
             send-advert true
         }
     }
     smp_affinity auto
     speed auto
 }
}
protocols {
 static {
     route6 ::/0 {
         next-hop <address removed>:4CC::1 {
         }
     }
 }
}

There is no firewall on for v6, I will enable that later when I get this working.

At the moment, VMs are connected to a bridge (eth1), and are receiving their proper ipv6 addresses via router adverts.

However, v6 traffic sent by the VMs don't seem to make it back quite right.

On a MTR from the VMs, the VMs can get to eth1, but nothing beyond that.

On a MTR from the web to the VM, the traffic drops off right before the VM. The first screenshot is to :4CC::2, while the second screenshot is to a VM.

Silvenga

That was a pain, it took me a while to get IPv6 working both ways under Dacentec. I could tell you what I did and it might help (I was using vanilla KVM)?

I setup my host to act as the gateway (taking 2607:XXX:XXX:1::1 for it's self).

iface eth0 inet6 static
        address 2607:XXX:XXX:1::1
        netmask 128
        gateway 2607:XXX:XXX::1

I enabled forwarding under IPv6 which disables accept_ra. I re-enabled it via setting 2. Then to allow packets to be proxied via the gateway I enabled proxy_ndp.

net.ipv6.conf.all.forwarding=1
net.ipv6.conf.eth0.accept_ra=2
net.ipv6.conf.br0.accept_ra=2
net.ipv6.conf.all.proxy_ndp=1

I setup up my bridge to use my host as the gateway taking the IPv6 /48 subnet.

iface br0 inet6 static
        address 2607:XXX:XXX:1::1
        netmask 48

I setup up the neigh proxy so that I could get packets to hit my host through 2607:XXX:XXX:1::1.

        up ip -6 neigh add proxy 2607:XXX:XXX:1::100 dev eth0
        up ip -6 neigh add proxy 2607:XXX:XXX:1::101 dev eth0
        up ip -6 neigh add proxy 2607:XXX:XXX:1::102 dev eth0

Then finally I setup my routes to get from my gateway to my VM's.

        up ip -6 route add       2607:XXX:XXX:1::100 dev br0
        up ip -6 route add       2607:XXX:XXX:1::101 dev br0
        up ip -6 route add       2607:XXX:XXX:1::102 dev br0

Without the routes I was able to access the VM over IPv6 if I pinged the gateway.

PrincessOfCats

Thanks!

You've pointed me in the right direction. I enabled forwarding/ra/ndp on VyOS, then I went to add the VM addresses via neighbor proxy. The entire setup runs on Proxmox with VyOS being the firewall. The VMs are running on a private bridge that is attached to VyOS.

Quite irritating just to get ipv6 support on the VMs though.

Edit:
Found an app named Ndppd which automatically manages the proxying. Works fine, new VMs get connection to ipv6 instantly.

hcuk94

@PrincessOfCats said:
Thanks!

You've pointed me in the right direction. I enabled forwarding/ra/ndp on VyOS, then I went to add the VM addresses via neighbor proxy. The entire setup runs on Proxmox with VyOS being the firewall. The VMs are running on a private bridge that is attached to VyOS.

Quite irritating just to get ipv6 support on the VMs though.

Edit:
Found an app named Ndppd which automatically manages the proxying. Works fine, new VMs get connection to ipv6 instantly.

Hi there, I realise this is a very old thread now, but I'm currently fighting a similar battle with a hypervisor running in OVH with their questionable IPv6 offering.

If by any chance you are still running this config would you mind sharing your working config for VyOS? Thanks!