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Having inaugurated my new OVH’s VPS SSD 1 I am greeted by a notification reading

Your instance is now linked to a free IPv6 in addition to the default IPv4.

Indeed I can see a “IPv6” and a “Gateway” fields.

Problem is: I can’t ping it using this IPv6. I read OVH documentation on the subject but didn’t see anything related to systemd-networkd; and I’m pretty sure it’s what’s being used.

I tried to edit the default /etc/systemd/network/eth0-dhcp.network like this:

[Match]
Name=eth0

[Network]
DHCP=ipv4

Address=2001:41d0:404:200::21e8/128
Gateway=2001:41d0:404:200::1

[DHCP]
UseMTU=true

Now ip -6 addr show shows me

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 2001:41d0:404:200::21e8/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::f816:3eff:fe97:9a63/64 scope link 
       valid_lft forever preferred_lft forever

ip -6 route shows

2001:41d0:404:200::/64 dev eth0 proto kernel metric 256 pref medium
fe80::/64 dev eth0 proto kernel metric 256 pref medium
default dev lo proto kernel metric 256 pref medium
default dev lo proto static metric 1024 pref medium
default via 2001:41d0:404:200::1 dev eth0 proto static metric 1024 pref medium

I can ping the gateway’s IP but pinging ipv6.google.com returns

Destination unreachable: No route

How can I configure my VPS to make it accessible using IPv6?

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1 Answer 1

Reset to default
-1

The only obvious problem I see with your network config is:

DHCP=yes

This should instead be:

DHCP=ipv4

You are obtaining an IPv4 address with DHCP but configuring IPv6 manually. Thus you only want to enable DHCP on IPv4.

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  • That makes sense; I updated the configuration but it still doesn’t work. I edited my question accordingly.
    – user538262
    Sep 4, 2019 at 7:43
  • @MatTheCat Well, obviously /128 is wrong also, but fortunately it seems to have ignored you there. The live state of the system looks correct. Or maybe it didn't ignore you? I can't ping that address either, but that doesn't necessarily mean anything. Did you try making an outgoing connection? Can you ping the gateway?
    – Michael Hampton
    Sep 4, 2019 at 7:47
  • Er I just copied 128 from OVH docs but I don't know what's that means ^^' I can ping the gateway but nothing else as it seems.
    – user538262
    Sep 4, 2019 at 7:50
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    @MatTheCat That should be /64, not /128. IPv6 subnets are always /64 except in some very unusual circumstances. I don't know why you would find something else in OVH's docs, but you should fix that.
    – Michael Hampton
    Sep 4, 2019 at 7:51
  • Okay so I remplaced /128 by /64. Running systemctl restart systemd-networkd does not seem to bring any change.
    – user538262
    Sep 4, 2019 at 7:54

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