Lack of IPv6 Support

[Shannon Barber]

Could better IPv6 support please be prioritized.
The change needed to make it work with Ubuntu containers is very minor.
It's one setting in one file that PVE overrides to the wrong value.

IPv6AcceptRA in /etc/systemd/network/eth0.network needs to be true not false.
IPv6AcceptRA = true

S

Post in thread 'Accepting RA on LXC'

Aug 10, 2025

This is still an issue for me, Whenever docker starts, ip6 default route disappears. I wrote a start up hook script.

I will keep checking if it works good, if it doesn't will post again.

/var/lib/vz/snippets/ipv6_accept_ra_fix.pl

#!/usr/bin/perl


# Ref: https://pve.proxmox.com/pve-docs/chapter-pct.html#_hookscripts
# Ref: Example: /usr/share/pve-docs/examples/guest-example-hookscript.pl
# Ref: https://forum.proxmox.com/threads/change-remove-hookscript-from-lxc-container.97567/#post-422023
# Ref: https://forum.proxmox.com/threads/post-start-script-for-lxc.36289/#post-504847...

• solonion

 

[damo2929]

have you send them a pull request on the git repo with the fix ?

 

[Stoiko Ivanov]

It's one setting in one file that PVE overrides to the wrong value.

IPv6AcceptRA in /etc/systemd/network/eth0.network needs to be true not false.
IPv6AcceptRA = true

from a quick look at the code: https://git.proxmox.com/?p=pve-cont...6f4769609c50caa6c8a7b91a91566080;hb=HEAD#l294
It should be set to true, if you set the containers IPv6 config to 'auto' (called SLAAC) in the GUI (did not test this explicitly though)

I hope this helps!

 

[Stoiko Ivanov]

have you send them a pull request on the git repo with the fix ?

Contributions are very welcome - thanks for the suggestion!
We use a mail-based workflow - see https://pve.proxmox.com/wiki/Developer_Documentation for submitting patches.

 

[Shannon Barber]

Here's the patch ...

diff --git a/src/PVE/LXC/Setup/Base.pm b/src/PVE/LXC/Setup/Base.pm
--- a/src/PVE/LXC/Setup/Base.pm
+++ b/src/PVE/LXC/Setup/Base.pm
@@ -267,6 +267,7 @@ sub setup_systemd_networkd {     if (defined(my $ip = $d->{ip6})) {
         if ($ip eq 'dhcp') {
             $dhcp |= $DHCP6;           $accept_ra = 'true';
       } elsif ($ip eq 'auto') {
           $accept_ra = 'true';
       } elsif ($ip ne 'manual') {

 

[Stoiko Ivanov]

Here's the patch ...

please send it to our development list - and provide a short explanation why this is needed in your case.

Thanks!

 

[Stoiko Ivanov]

Looking through our bugzilla (which is the place where feature requests and bug-reports are tracked) I found:
https://bugzilla.proxmox.com/show_bug.cgi?id=5538
which should align with your issue - please note your suggestion there (it gets more visibility).

Thanks!

 

[anutrix]

Is there a specific reason why Proxmox Node/host GUI/web-portal network settings does not support SLAAC configuration like it's possible for LXCs?
I know I can modify `/etc/network/interfaces` but changes there would be removed when anything in the GUI is modified afterwards.