Hi everyone,
I’d like to share an issue I encountered after upgrading from Proxmox VE 8 to PVE 9, which took me nearly a full day to troubleshoot. Hopefully this helps someone else in the future.
After upgrading from PVE 8 to PVE 9, my Proxmox host was no longer receiving IPv6 addresses via Router Advertisement (RA).
My bridge configuration on the PVE host was:
Important note:
This allows the host to accept RA even when forwarding is enabled.
From the PVE side, everything looked correct.
My OpenWrt router VM:
When I disabled STP on the OpenWrt LAN bridge, IPv6 was immediately obtained on the PVE host.
This single setting caused a full day of debugging for me.
Hope this helps someone save time.
I’d like to share an issue I encountered after upgrading from Proxmox VE 8 to PVE 9, which took me nearly a full day to troubleshoot. Hopefully this helps someone else in the future.
The Situation
After upgrading from PVE 8 to PVE 9, my Proxmox host was no longer receiving IPv6 addresses via Router Advertisement (RA).
My bridge configuration on the PVE host was:
Code:
auto vmbr0
iface vmbr0 inet static
address 172.16.1.251/24
gateway 172.16.1.1
bridge-ports enp1s0f0
bridge-stp off
bridge-fd 0
post-up echo 2 > /proc/sys/net/ipv6/conf/vmbr0/accept_raImportant note:
Code:
echo 2 > /proc/sys/net/ipv6/conf/vmbr0/accept_raThis allows the host to accept RA even when forwarding is enabled.
From the PVE side, everything looked correct.
The Real Cause
The actual issue had nothing to do with PVE 9 itself.My OpenWrt router VM:
- Its LAN interface is bridged to vmbr0
- The LAN bridge device in OpenWrt had STP enabled
When I disabled STP on the OpenWrt LAN bridge, IPv6 was immediately obtained on the PVE host.
Final Notes
If after upgrading to PVE 9:- Your bridge looks correct
- accept_ra=2 is set
- DHCPv6 works manually but RA does not
This single setting caused a full day of debugging for me.
Hope this helps someone save time.
