IPv6 proxmox OVH

More to remind me than anything else…

With the help of https://forum.ovh.co.uk/showthread.php?5844-IPv6-with-Proxy-ARP

Since OVH do not yet support IPv6 on Vrack (GRR!) you have to use the Servers /64 but given the horrible way they allocate it (Sorry guys but it really *IS* horrible)

This assumes your server already had working IPv6, if proxmox 4.x was installed by the OVH build system it probably does, It also assumes your virtual machines aren’t directly on the WAN interface and Using their virutal mac/failover IP system (which if you use Vrack they probably aren’t)

Step1:  Change the subnetmask/prefix length on the WAN (Public) interface to /128 (It will still work because the way OVH do routing)

Step2 add an IP to the INTERNAL bridge (Assuming your VMs are behind a firewall/on an internal bridge) e.g xxxx:xxxx:xxxx:xxxx::2 /64

Step3: configure Ip’s on the VM’s e.g xxxx:xxxx:xxxx:xxxx::3 set their gateway to the IP you set on the internal bridge (E.g ::2)

Step4: add the following to /etc/rc.local


echo 1 > /proc/sys/net/ipv6/conf/all/proxy_ndp
echo 1 > /proc/sys/net/ipv6/conf/all/forwarding
ip -6 neigh add proxy xxxx:xxxx:xxx:xxxx::3 dev vmbr0

Step5: Check the VM now has IPv6 connectivty
Step6: Enable a Firewall and configure approprately

Step7: Repeat 3-6 for each addational VM (with a new IPv6 obvisously), also you only need the neigh add proxy line for the addational Ip’s since you’ve already enabled forwarding in the first 2 lines.