Proxmox Not Automatically Assigning IPv6 via RA/DHCPv6

[Kjume]

Hello,


I am experiencing an issue where my Proxmox servers are not automatically receiving a public IPv6 address via Router Advertisements (RA) or DHCPv6, while other devices on the same network (such as my Windows laptop) receive an IPv6 address immediately.

Network Setup:​

• My router is configured to provide IPv6 addresses using DHCPv6.
• A Windows machine connected to the same network automatically receives a public IPv6 address and is reachable from the internet.
• However, Proxmox (running on Debian) only receives a link-local address (fe80::/64) but no global IPv6 address.

Troubleshooting Steps Taken:​

1. Checked IPv6 addresses on Proxmox:
   
   ip -6 addr show vmbr0
   
   • Only a link-local address is assigned, no global IPv6.
2. Tried requesting an address manually:
   
   dhclient -6 -v vmbr0
   
   • No public IPv6 is assigned.
3. Verified IPv6 routes:
   
   >ip -6 route
   • No default IPv6 route exists.
     
4. Manually assigned an IPv6 address for testing:
   
   • After manual assignment, IPv6 does not work properly.

Question:​

• Why is Proxmox not automatically receiving an IPv6 address via DHCPv6 or Router Advertisements, even though other devices on the same network do?
• Is there a known issue with Proxmox not handling RA/DHCPv6 correctly?
• What is the recommended way to configure Proxmox to ensure it automatically obtains a public IPv6 address upon network restart?

Thank you for your assistance.

 

[IsThisThingOn]

• Why is Proxmox not automatically receiving an IPv6 address via DHCPv6 or Router Advertisements, even though other devices on the same network do?

Because Proxmox is not using auto settings but inet manual. So no auto for IPv4 and no auto for IPv6.

Not the default I would choose, but it is what it is.

Fortunately you can change this. Proxmox VE is using the Linux network stack.
https://pve.proxmox.com/wiki/Network_Configuration

 

[Kjume]

Because Proxmox is not using auto settings but inet manual. So no auto for IPv4 and no auto for IPv6.

Not the default I would choose, but it is what it is.

Fortunately you can change this. Proxmox VE is using the Linux network stack.
https://pve.proxmox.com/wiki/Network_Configuration

idk why but not work at all... i cant manually set IPV6 for my proxmox servers... another devices or normal linux systems works okay but proxmox dont wanna function on IPV6 and idk why... what i can see its "known" problem about IP6 on proxmox i see threads from 2021 and they still not solved...

idk how to set up IPV6 like a normal person btw IPV6 is smth new for me...

 

[IsThisThingOn]

can't test it right now but can't you change:

auto vmbr0
iface vmbr0 inet static
        address 10.0.10.2/24
        gateway 10.0.10.1
        bridge-ports ens1
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094

to somthing like this:

auto vmbr0
iface vmbr0 inet auto

 

[Kjume]

can't test it right now but can't you change:

auto vmbr0
iface vmbr0 inet static
        address 10.0.10.2/24
        gateway 10.0.10.1
        bridge-ports ens1
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094

to somthing like this:

auto vmbr0
iface vmbr0 inet auto

Nope not work at all...

Idk why proxmox can't support IPv 6 i think inet Is Broken

 

[IsThisThingOn]

Nope not work at all...

what do you mean by that?

 

[Johannes S]

Idk why proxmox can't support IPv 6 i think inet Is Broken

But it does support IPv6 (like any Debian) as long as you don't disable it. Can you please post the output of this commands from the console?

# Display information about the configured network adresses
ip addr
# Display used kernel boot options, I want to know whether IPv6 was disabled
cat /proc/cmdline
# Display all sysctl settings so we can determine whether IPv6 was disabled with sysctl
sysctl -a

On my boxes PVE has IPv6, but like IPv4 you need to configure it.