secondary IPV6 address add gateway and interface problem in VPS ON / openNebula.

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After several manual attempts directly in the shell on the vps I decided to ask for support via email. A nice and friendly technician gave me the following link https://kb.wedos.com/cs/vps-on/vps-on-pridani-ipv6-adresy/#pridani-druhe-ipv6-adresy

i followed the guide and i finally managed to add additional ipv6 to the ::/56 subnet assigned in the opennebula panel. As you can see from the following images I have attached and added a total of 5 ipv6.

After updating the changes and restarting the server, the situation is as follows. Given that it is absurd from my point of view that openNebula raises 5 interfaces eth1 for ::1, eth2 for ::2, eth3 ::3 .. in the config and assigning a single ipv6 address for each interface being precisely from the same subnet and not there is an attempt to delegate to a user outside the network. Having said that, I rebooted the server and was expecting that /etc/network/interfaces had already taken the configuration but to my surprise it didn’t.

So I tried to add static addresses at startup without specifying the gateway for all addresses but only for the starting ::1 (see example). Result ::1 responds to pings and all others ::2 ::3 ::4 ::5 do not respond. I then tried to add the gateway for each ip with the result that ::5 replied and ::4 ::3 ::2 ::1 no longer replied.

1) vim /etc/network/interfaces

auto eth1
iface eth1 inet6 static
  address 2a02:x:x:x::1
  netmask 56
  autoconf 0
  accept_ra 0
  gateway 2a02:x:x:x::1 # opennebula specified in the panel
 auto eth2
iface eth2 inet6 static
  address 2a02:x:x:x::2
  netmask 56
# gateway 2a02:x:x:x::1 (test add ipv6 without gateway)
...
continue up to 5

At this point I went to add by hand following information from the main opennebula panel and then to check the routes on the vps and I realized that the situation is the following.

~$ ip -6 r s
2a02:x:x:x::/56 dev eth1 proto kernel metric 256 pref medium
2a02:x:x:x::/56 dev eth2 proto kernel metric 256 pref medium
fe80::/64 dev eth0 proto kernel metric 256 pref medium
fe80::/64 dev eth1 proto kernel metric 256 pref medium
fe80::/64 dev eth2 proto kernel metric 256 pref medium
default via 2a02:x:x:x::1 dev eth1 metric 1024 onlink pref medium
~$ route -6
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
2a02:x:x:x::/56           [::]                       U    256 2     0 eth1
2a02:x:x:x::/56           [::]                       U    256 1     0 eth2
fe80::/64                      [::]                       U    256 2     0 eth0
fe80::/64                      [::]                       U    256 2     0 eth1
fe80::/64                      [::]                       U    256 1     0 eth2
[::]/0                         2a02:2b88:2:500::1         UGH  1024 2     0 eth1
ip6-localhost/128              [::]                       Un   0   4     0 lo
address/128               [::]                       Un   0   4     0 eth1
2a02:x:x:x::2/128         [::]                       Un   0   2     0 eth2
fe80::59ff:fedd:d89e/128       [::]                       Un   0   4     0 eth0
fe80::e8ff:fe41:9a4/128        [::]                       Un   0   4     0 eth1
fe80::e8ff:fe41:9a5/128        [::]                       Un   0   2     0 eth2
ff00::/8                       [::]                       U    256 3     0 eth0
ff00::/8                       [::]                       U    256 2     0 eth1
ff00::/8                       [::]                       U    256 2     0 eth2
[::]/0                         [::]                       !n   -1  1     0 lo

ifconfig:

I realized then and I tried add manually add the gateway for eth2, eth3 … obviously with result:

~$ sudo ip  -6 r a default via 2a02:x:x:x::1 dev eth2 
RTNETLINK answers: File exists

at this point I wonder how it is right to do. Theoretically I should remove the gateway which is only assigned to eth1 and globally assign it to everything. Correct?

Example:

~$ sudo ip -6 r d default via 2a02:x:x:x::1 dev eth1

and add new global gateway without dev

~$ sudo ip -6 r a default via 2a02:x:x:x::1

I have a feeling it won’t work. Did you have the same problem? do you have any ideas about it?

Thanks for your help.

Role: Customer
Question is closed for new answers.
MB313456 Selected answer as best 26. 11. 2021
0

I apologize if I write below but I have not found a way to edit the previous post.

I add as information. I tried manually to add address and the gateway route for interface eth2 with ipv6 2a02:x:x:x::2

~$ sudo ifconfig eth2 up                                                            #mount interface

~$ sudo ip -6 a a 2a02:x:x:x::2/56 dev eth2                              #add my secondary ipv6 address to eth2

~$ sudo route -A inet6 add default gw 2a02:x:x:x::1 dev eth2 metric 1024  #add default gateway to eth2
~$ sudo ip -6 r s
2a02:x:x:x::/56 dev eth1 proto kernel metric 256 pref medium          #my subnet address ::1
2a02:x:x:x::/56 dev eth2 proto kernel metric 256 pref medium           #my subnet address ::2
fe80::/64 dev eth0 proto kernel metric 256 pref medium
fe80::/64 dev eth1 proto kernel metric 256 pref medium
fe80::/64 dev eth2 proto kernel metric 256 pref medium
default metric 1024 pref medium
nexthop via 2a02:x:x:x::1 dev eth1 weight 1 onlink                  #default gw for my subnet
nexthop via 2a02:x:x:x::1 dev eth2 weight 1                             #default gw for my subnet

Same result obtained previously. Adding the gateway also on eth2 this works and responds to the ping, but eth1 with its address :: 1 stops working.

Anyone who has had the need to raise additional secondary ipv6 address on vps or dedicated?
Is there perhaps the possibility of setting from the opennebula panel so that the secondary addresses are always associated with eth1?

Forum admin question: I noticed and read that the questions asked here are not automatically switched to the * .cz help profile. Can I link this thread to help.wedos.cz as well?

Role: Customer
MV270050 Changed status to publish 23. 11. 2021
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