[SOLVED] ipv6 configuration problem with "vm bridge".

[Ellie]

Hello !
I have installed a proxmox VE 7.3-4 on top of debian 11 (the distro wasn't available by any other mean) on a public cloud instance at ovh as a test project.
Everything could be fine except that I can't figure out how to have a properly configured ipv6 internet access on my VM/CT.

I have created a vmbr0 for the management layer with ipv4 and ipv6 assigned to the nic, and a vmbr1 for the VMs

ipv4 is working fine on host and on VMs, no problem there.
ipv6 is working fine on host, but not on VMs. I'm sure that I'm missing a very stupid thing, but I've spent hours on this and I can't see clearly anymore.
Of course, I don't want to do NAT with ipv6, I want each VM to have one of the public ipv6 that are available.

Any help would be invaluable ! Thanks a lot ! (and happy new year if it's not too late where you live

Here's my proxmox /etc/network/interfaces :

auto lo
iface lo inet loopback

iface eno1 inet manual

auto vmbr0
iface vmbr0 inet static
address XX.XX.154.19/32
gateway XX.XX.154.254
bridge-ports eno1
bridge-stp off
bridge-fd 0
bridge-vlan-aware yes
bridge-vids 2-4094

iface vmbr0 inet6 static
address XXXX:XXXX:101:c013::0001/64
gateway XXXX:XXXX:101:c0ff:ff:ff:ff:ff

auto vmbr1
iface vmbr1 inet static
address 10.10.10.1/24
bridge-ports none
bridge-stp off
bridge-fd 0

post-up echo 1 > /proc/sys/net/ipv4/ip_forward
post-up iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o vmbr0 -j MASQUERADE
post-down iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o vmbr0 -j MASQUERADE

iface vmbr1 inet6 static
address XXXX:XXXX:101:c013::0002/64
gateway XXXX:XXXX:101:c013::0001

 

[Ellie]

Ok. So I finally got it working, while redoing again what I thought I had already done almost a 100 times. Maybe I had missed a reboot one of the previous 100 times.
Happy to have managed that in a clean way.
Cheers !

Is there a way to "close" a thread ?

 

[Neobin]

Is there a way to "close" a thread ?

You can edit your initial/first post and choose "[SOLVED]" as prefix from the drop-down menu left beside the title.

 

[vihai]

Hello,

You may be experiencing an issue with multicast snooping which is breaking IPv6 neighbor discovery.

I'm troubleshooting this problem right now.

I had my VMs with IPv6 issues, than I had them working after a reboot, then, after few days, suddenly, I had IPv6 between the boxes break.

I found that disabling multicast snooping fixed the issue:

echo 0 > /sys/devices/virtual/net/XXXXX/bridge/multicast_snooping

 

[Ellie]

Hello,

You may be experiencing an issue with multicast snooping which is breaking IPv6 neighbor discovery.

I'm troubleshooting this problem right now.

I had my VMs with IPv6 issues, than I had them working after a reboot, then, after few days, suddenly, I had IPv6 between the boxes break.

I found that disabling multicast snooping fixed the issue:

echo 0 > /sys/devices/virtual/net/XXXXX/bridge/multicast_snooping

Thanks a lot for this tip ! I'll preciously store it with all proxmox related info in case ipv6 troubles me again For now all is alright, so, fingers crossed !