Getting IPv6 to work on OVH Kimsufi server is not easy. Configuring Routed IPv6 for NATed virtual machines is even a disaster. After about 5 hours of struggle I finally come up with a working config.
The goal of this post is to document how to go from a blank server into a proxmox server with NAT IPv4 and Routed IPv6 KVM virtual machines set up.
[ ↑ ]
First thing first, you’ll need a server from Kimsufi. Here’s my KS-3C server specs for example.
CPU: Intel(R) Core(TM) i3-2130 CPU @ 3.40GHz
RAM: 8 GiB
Networking: 100mbps unmetered, 1x IPv4, 1xIPv6
Storage: 1x 2TB SATA
Please do note that, although only 1 IPv6 is assigned to the server, you can actually use (or steal) the entire /56 range (Daniele, 2016). I’d recommend using your own /64 space.
Kimsufi comes with an automatic Debian installer which is nice by the way, however it’s not a completelyvanilla installation as OVH will add some scripts and changes to the system. If you are not a paranoid like me, you can jump straight to first boot section and save a few minutes.
[ ↑ ]
I was basically following the blog post (Félizard, 2012) with a few changes to my own needs since It’s a proxmox server. I’d recommend installing Debian from the management panel first, as it writes OS type into its own database may avoid some issues afterwards. When the installation is done, you can then boot into rescue CD
Now, partition your hard drive. Wipe all partitions and recreate them according to your needs. Mine looks like this:
GPT: [BIOS Boot] [Root 40GiB] [Swap 8GiB] [LVM *GiB] Device Start End Sectors Size Type /dev/sda1 64 4095 4032 2M BIOS boot /dev/sda2 4096 83886079 83881984 40G Linux filesystem /dev/sda3 83886080 100663295 16777216 8G Linux swap /dev/sda4 100663296 3907029134 3806365839 1.8T Linux LVM
fdisk /dev/sda mkfs.ext4 /dev/sda2 mkdir /target mount /dev/sda2 /target debootstrap --verbose --arch amd64 --variant minbase --include dialog,vim,ifupdown,netbase,net-tools,ssh,systemd,systemd-sysv,locales,wget stretch /target http://debian.bhs.mirrors.ovh.net/debian mount -t proc none /target/proc mount -t sysfs none /target/sys mount -o bind /dev /target/dev chroot /target /bin/bash echo "deb http://download.proxmox.com/debian/pve stretch pve-no-subscription" > /etc/apt/sources.list.d/pve-install-repo.list wget http://download.proxmox.com/debian/proxmox-ve-release-5.x.gpg -O /etc/apt/trusted.gpg.d/proxmox-ve-release-5.x.gpg apt update apt install proxmox-ve apt upgrade rm /etc/apt/sources.list.d/pve-enterprise.list vi /etc/fstab vi /etc/hostname vi /etc/hosts vi /etc/ssh/sshd_config passwd vi /etc/network/interfaces
Networking is the tricky part. Debian Stretch uses so called
Predictable Network Interface Names, which is unpredictable until you actually see it. Luckily, for KS-3C and KS-4C, it seems to be just
eno1. For other types of server, please use systemd-networkd wildcard matching (Porquet, 2016) to obtain your initial access to the server.
# Example of interfaces file auto lo iface lo inet loopback auto eno1 iface eno1 inet static address 220.127.116.11 netmask 255.255.255.0 gateway 18.104.22.168
When everything is done, leave the chroot and reboot the server. Remember to switch back to HDD boot in your kimsufi management panel first.
exit umount /target/proc umount /target/sys umount /target/dev umount /target reboot
[ ↑ ]
As usual, many things to do like setting up swap and LVM, installing missing packages.
And of course, configur network bridges for VMs.
Note: bridging on eno1 is not absolutely necessary — use
eno1 instead if you choose to do so.
# Example of interfaces file source-directory /etc/network/interfaces.d auto lo iface lo inet loopback auto eno1 iface eno1 inet manual auto vmbr0 iface vmbr0 inet static address 22.214.171.124 netmask 255.255.255.0 gateway 126.96.36.199 bridge_ports eno1 bridge_stp off bridge_fd 0 iface vmbr0 inet6 static address 2607:5300:66:6789::ffff netmask 128 post-up sleep 5; /sbin/ip -6 route add 2607:5300:66:67ff:ff:ff:ff:ff dev vmbr0 post-up sleep 5; /sbin/ip -6 route add default via 2607:5300:66:67ff:ff:ff:ff:ff pre-down /sbin/ip -6 route del default via 2607:5300:66:67ff:ff:ff:ff:ff pre-down /sbin/ip -6 route del 2607:5300:66:67ff:ff:ff:ff:ff dev vmbr0 auto vmbr1 iface vmbr1 inet static address 172.16.0.1 netmask 255.255.0.0 bridge_ports none bridge_stp off bridge_fd 0 iface vmbr1 inet6 static address 2607:5300:66:6789::1 netmask 64
This is an example config for dual stack VMs with IPv4 NATed and IPv6 routed.
Internet <==> [(vmbr0) Host (vmbr1)] <==> [(ens18) Virtual Machine ]
Here the important part is netmask 128 on the vmbr0. The IPs are not important as longs as they are all different. I picked
::ffff for host and
::1 for subnet gateway. Feel free to choose IPs on your discretion. Same applies to private IPv4 subnet.
Check if you can ping to any IPv6 site like
/etc/sysctl.conf and enable traffic forwarding and ndp proxying.
# Example of sysctl.conf file net.ipv4.ip_forward = 1 net.ipv6.conf.all.forwarding = 1 net.ipv6.conf.all.proxy_ndp = 1 vm.swappiness = 10 net.ipv6.bindv6only = 1
And reboot for networking to take effects.
[ ↑ ]
NAT IPv4 is achieved by iptables. Install
iptables-persistent package using apt, and modify
/etc/iptables/rules.v4 to properly NAT and forward ports for VMs.
# Example of /etc/iptables/rules.v4 *nat -A POSTROUTING -s 172.16.0.0/16 -o vmbr0 -j MASQUERADE -A PREROUTING -i vmbr0 -p tcp -m tcp --dport 10022 -j DNAT --to-destination 172.16.0.100:22 COMMIT
Load iptables with
iptables-restore < /etc/iptables/rules.v4.
[ ↑ ]
Routing IPv6 on OVH network was such a headache and not much useful tutorial can be found at the other end of search engine. A typical strategy is to use
ip -6 neigh add proxy command (Groarke, 2010) to manually add all IPv6 addresses into proxy list. It might be acceptable if you only have 1 or 2 VMs, but this is still tricky to accomplish (you have to write startup scripts, etc).
Luckily, there’s a small tool called npd6 which does this for you, intelligently and easily.
wget http://ftp.ca.debian.org/debian/pool/main/n/npd6/npd6_1.1.0-1_amd64.deb dpkg -i npd6_1.1.0-1_amd64.deb vi /etc/npd6.conf
# Example of /etc/npd6.conf prefix = 2607:5300:66:6789: interface = vmbr0 ralogging = off listlogging = off
Restart the service and it should do its job. Whenever a new IPv6 is configured on the private side, npd6 will respond to its corresponding neighbor solicitation request for that VM. Thank you Sean for writing this!
Networking Config inside VM
[ ↑ ]
I tend to use
systemd-networkd and it couldn’t be easier after someone else has done the heavylifting.
[Match] Name=ens18 [Network] Address=172.16.0.102/16 Gateway=172.16.0.1 Address=2607:5300:66:6789::102/64 Gateway=2607:5300:66:6789::1
[ ↑ ]
Daniele / Otacon22 (2016, Febuary 21). IPv6 setup in two hosting providers compared: awful (OVH) and awesome (Online.net). Retrieved November 27, 2017, from https://otacon22.com/2016/02/21/two-hosting-providers-ipv6-setups-compared-ovh-online-net/
Félizard, C. (2012, November 05). How to install a vanilla Debian on a Kimsufi. Retrieved November 27, 2017, from https://infertux.com/posts/2012/11/05/how-to-install-a-vanilla-debian-on-a-kimsufi/
Porquet, J. (2016, May 08). Howto install a vanilla ArchLinux on a Kimsufi/OVH server. Retrieved November 27, 2017, from https://joel.porquet.org/wiki/hacking/archlinux_kimsufi/
Groarke, S. (2010, March 24). IPv6 – Proxy the neighbors. Retrieved November 27, 2017, from https://www.ipsidixit.net/2010/03/24/239/