Static IPv6 address not configured

[hpcraith]

My Proxmox: Virtual Environment 6.2-10
We have a dedicated IPv6-range

in /etc/network/interfaces:

auto enp94s0f0
iface enp94s0f0 inet static
address xxx.xx.4.210
netmask 255.255.255.192
gateway 141.58.4.254

iface enp94s0f0 inet6 static
address xxxx:xxx:xxxx:194::x2
netmask 64
gateway xxxx:xxx:xxxx:194::1

After boot the IPv6 address is not configured.
I can set the address using

ip -6 address add xxxx:xxx:xxxx:194::x2/64 dev enp94s0f0
and ping it.

sysctl net.ipv6.conf |& grep autoconf

net.ipv6.conf.enp94s0f0.autoconf = 0
net.ipv6.conf.enp94s0f1.autoconf = 0

Any idea?

 

[hpcraith]

I am really astonished that nobody has an answer to my problem. The Proxmox staff at least should
have an answer. I tried many things without success.
Now I found a solution. I moved

iface enp94s0f0 inet6 static
address xxxx:xxx:xxxx:194::x2
netmask 64
gateway xxxx:xxx:xxxx:194::1

to the top of /etc/network/interfaces and commented out (#) the inet part.
After reboot the IPv6 address of enp94s0f0 was configured!!

Then I uncommented the inet part. And both IPv4 and IPv6 addresses were
configured. This is really weird.

There is still an error, which I do not understand.

root@vwsrv1:~# systemctl status networking
● networking.service - Raise network interfaces
Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Mon 2020-10-12 15:40:52 CEST; 18min ago
Docs: man:interfaces(5)
Process: 1266 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)
Main PID: 1266 (code=exited, status=1/FAILURE)

Oct 12 15:40:50 vwsrv1 systemd[1]: Starting Raise network interfaces...
Oct 12 15:40:52 vwsrv1 ifup[1266]: Waiting for DAD... Done
Oct 12 15:40:52 vwsrv1 ifup[1266]: Waiting for vmbr0 to get ready (MAXWAIT is 2 seconds).
Oct 12 15:40:52 vwsrv1 ifup[1266]: RTNETLINK answers: File exists
Oct 12 15:40:52 vwsrv1 ifup[1266]: ifup: failed to bring up vmbr0
Oct 12 15:40:52 vwsrv1 systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Oct 12 15:40:52 vwsrv1 systemd[1]: networking.service: Failed with result 'exit-code'.
Oct 12 15:40:52 vwsrv1 systemd[1]: Failed to start Raise network interfaces.
root@vwsrv1:~#

vmbr0 is up and configured!!

Hopefully I will also find the reason for that behaviour!