Kernel proxmox-kernel-6.14.11-4-pve-signed IPv6 Issues

[bergerwo]

Hi,
It seems there’s a problem with proxmox-kernel-6.14.11-4-pve-signed and IPv6.
I’m running OPNsense with radvd on PVE.

On kernel version 6.14.11-4, IPv6 stops working, while 6.14.11-3 is not affected.
The issue is reproducible every time I boot into 6.14.11-4.

Has anyone else experienced this issue?

Thanks and Best regards,
Wolfgang

 

[bergerwo]

Update: IPv6 stopped working again. VM to VM communication on the same hypervisor is not possible as well. I am running on kernel (-3). Does somebody know about ipv6 related changes in the last updated packages ~ 1 week?

 

[bergerwo]

Update: It looks like the OPNsense radvd service is the problem here. As soon as I restart radvd, IPv6 starts working again. It seems that the radvd interval times out or does not renew by itself. Only a manual restart of the process temporarily fixes the problem.

 

[bergerwo]

Update: In case someone else reads my monolog. -> Looks like the problem is unrelated to proxmox.

 

[bergerwo]

Update: The issue was not OPNsense radvd related. Disabling Multicast Snooping on vmbrXXX was the solution!

This can be done with the following command:

echo 0 > /sys/class/net/vmbrXXX/bridge/multicast_snooping

To make the change persistent, add the following line to your bridge configuration in

/etc/network/interfaces:bridge-multicast-snooping 0

 

[bergerwo]

one last word to this topic:

the setting in /etc/network/interfaces depends on timing and can be overwritten by proxmox system on startup. you can make it persistent with a systemd service that starts after network target.

####

[Unit]

Description=Disable bridge multicast snooping

After=network.target

[Service]

Type=oneshot

ExecStart=/bin/sh -c "echo 0 > /sys/class/net/vmbr0/bridge/multicast_snooping"

[Install]

WantedBy=multi-user.target

####

systemctl enable disable-mld-snooping.service
systemctl start disable-mld-snooping.service

####

After that this output must be empty: bridge mdb show

over and out - mic drop.