I have a cloud instance on OVH which is accessible over IPv4 but not IPv6. It's running Ubuntu 18.04. I've found conflicting advice about using netplan vs configuring systemd-networkd directly, but all of the things I've tried don't seem to have any effect.
In OVH's web interface I have these addresses defined for me:
IPv6: 2607:5300:201:2100::5d4
Gateway: 2607:5300:201:2100::1
According to the guides I've read, I've configured netplan like this:
/etc/netplan/90-ipv6.yml
network:
ethernets:
ens3:
match:
macaddress: fa:16:3e:53:64:ce
set-name: ens3
addresses:
- 2607:5300:201:2100::5d4/64
gateway6: 2607:5300:201:2100::1
nameservers:
addresses:
- 2001:41d0:3:163::1
version: 2
And systemd-networkd like this:
/etc/systemd/network/10-ens3.network
[Match]
Name=ens3
[Network]
DHCP=ipv4
Gateway=2607:5300:201:2100::1
DNS=2001:41d0:3:163::1
Destination=2607:5300:201:2100::1
[Address]
Address=2607:5300:201:2100::5d4/64
[Route]
Destination=2607:5300:201:2100::1
Scope=link
My ip addr
output looks like this:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether fa:16:3e:53:64:ce brd ff:ff:ff:ff:ff:ff
inet 54.39.191.97/32 scope global dynamic ens3
valid_lft 85848sec preferred_lft 85848sec
inet6 2607:5300:201:2100::5d4/0 scope global
valid_lft forever preferred_lft forever
inet6 fe80::f816:3eff:fe53:64ce/64 scope link
valid_lft forever preferred_lft forever
I can ping the gateway and get a response. However I cannot get a response from the server from any other location over IPv6, and a ping6 google.com
from this server results in:
PING google.com(yul02s05-in-x0e.1e100.net (2607:f8b0:4020:805::200e)) 56 data bytes
From [hostname] (2607:5300:201:2100::5d4) icmp_seq=1 Destination unreachable: Address unreachable
...
--- google.com ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 4085ms
The only thing I haven't tried is rebooting the server, as it's live and I'd really rather not.
What am I missing? I don't really know what I'm doing, so it might be something very obvious.
Thanks!
EDIT: Updated the prefix to /64. This configuration also doesn't work.
Best Answer
The correct IPv6 prefix for OVHcloud VPS is /64, not /128 or /0.