[SOLVED] IPv6 problems with Hetzner (did work before)

Jun 17, 2021
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Hello,

We have the following problem and I have no more ideas what could be wrong
. I can no longer reach two of our three hosts in a small cluster at Hetzner via IPv6. In my opinion, everything is set up correctly and it has already worked as it is set up. We have split up a larger cluster, kept two hosts and added another server, the new server is also accessible via IPv6. All of this actually worked until it stopped working...
What could I have missed?

The Hosts:
Hyperion (old)
Mimas (old)
Dione (new)

Facts:
3 Nodes, Proxmox 8.2.2
IPv4 (192.168.100.0/24) Cluster Network via vswitch
we removed seperate nics on the old nodes which we used as a ceph network

- ssh works fine from all nodes to all nodes
- I already renewed all ssh keys
- The web interface shows a ‘Connection error - Timeout’ when I want to edit Dione from Hyperion or Mimas.
- It is possible to edit Hyperion and Mimas from Dione web ui.
- IP forwarding s enabled
- I can't ping the old hosts
- same config does work on Dione

IPv6 is enabled
Code:
➜  ~ cat /proc/sys/net/ipv6/conf/all/disable_ipv6
0

/etc/network/interfaces
Code:
auto lo
iface lo inet loopback


iface enp7s0 inet manual


iface enp7s0.4000 inet manual
        mtu 1400


iface enp7s0.4001 inet manual
        mtu 1400


auto vmbr0
iface vmbr0 inet static
        address 65.xx.xx.xx/32
        gateway 65.21.79.129
        bridge-ports enp7s0
        bridge-stp off
        bridge-fd 0
#Hostnetwork


iface vmbr0 inet6 static
        address 2a01:4f9:xx:xxxx::2/64
        gateway fe80::1

[snip]
 
Hi,

"have you removed all servers then restarted the vSwitch and afterwards added them back? This is sometimes needed."

This is actually a statement which I got from Hetzner Support.
 
Hi,

"have you removed all servers then restarted the vSwitch and afterwards added them back? This is sometimes needed."

This is actually a statement which I got from Hetzner Support.
Yes, I created a new vswitch because I got the same statement from Hetzner :)
 
On one environment I've been what sounds like a similar issue. Other environments with same pve version and similar HW have been fine.

For the environment with issues, adding "bridge-mcsnoop 0" to our vmbr0/vlan-aware bridge has resolved. Ref https://forum.proxmox.com/threads/ipv6-neighbor-solicitation-not-forwarded-to-vm.96758/
This didn't helped. This is for IPv6 communication on the bridge right? I cant reach the both old host from the internet via ipv6 too.
 
This didn't helped. This is for IPv6 communication on the bridge right? I cant reach the both old host from the internet via ipv6 too.
Communication both on the bridge and external to the bridge (over bond0) for host/node and VMs.

The combined config looking like:

Code:
auto vmbr0
iface vmbr0 inet manual
        bridge-ports bond0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        mtu 9000
        bridge-mcsnoop 0
#Default VLAN Bridge

auto vmbr0.1
iface vmbr0.1 inet static
        address xx.xx.xx.144/24
        gateway xx.xx.xx.1
#Hypervisor Management

iface vmbr0.1 inet6 static
        address xxxx:xxxx:xxxx:xxxx::144/64
        gateway xxxx:xxxx:xxxx:xxxx::1
 
iface vmbr0.1 inet6 static
address xxxx:xxxx:xxxx:xxxx::144/64
gateway xxxx:xxxx:xxxx:xxxx::1 <<---- where do you get this from?

Normally, in my home lab, which of course use different IPv6 coonfig, I'd use
gateway fe80::1

But that's reported stale here....
 

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