How to configure IPv6?

[dekiesel]

To ensure that this isn't a XY-problem let me preface this by outlining what I am trying to do.

I would like to use matter and thread on a lxc each. Both containers need IPv6 connectivity.

I've stood up a matter-LXC and ran

python-matter-server:~# ping6 google.com
PING google.com (2a00:1450:4001:81c::200e): 56 data bytes
ping6: sendto: Network unreachable

Which means there is something wrong with my ipv6 setup.

What else does the container say?

python-matter-server:~# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth101@if120: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether 22:29:80:4f:c0:cc brd ff:ff:ff:ff:ff:ff
    inet 10.1.101.180/24 brd 10.1.101.255 scope global eth101
       valid_lft forever preferred_lft forever
    inet6 fd54:bac3:aabe:339d:2029:80ff:fe4f:c0cc/64 scope global dynamic flags 100
       valid_lft 1636sec preferred_lft 1636sec
    inet6 fe80::2029:80ff:fe4f:c0cc/64 scope link
       valid_lft forever preferred_lft forever
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN
    link/ether 02:42:35:6f:a8:d5 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever

To the best of my knowledge I have activated IPv6 on my proxmox host

root@pve:~# cat /etc/network/interfaces


auto lo
iface lo inet loopback

iface eno1 inet manual

auto vmbr0.100
iface vmbr0.100 inet static
        address  10.1.100.12/24
        gateway  10.1.100.1

auto vmbr0
iface vmbr0 inet manual
    bridge-ports eno1
    bridge-stp off
    bridge-fd 0
    bridge-vlan-aware yes
    bridge-vids 2-4094

iface vmbr0 inet6 dhcp
    gateway fd00::1
    accept_ra 2

And more from the host:

root@pve:~# ip address show dev  vmbr0
3: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether b0:0c:d1:62:a6:19 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::b20c:d1ff:fe62:a619/64 scope link
       valid_lft forever preferred_lft forever
root@pve:~#

But I am still seeing ping6: sendto: Network unreachable.
Could anybody let me know what I need to check?
Thank you!

 

[readyspace]

Hi, it seems like your host’s vmbr0 only shows link-local (fe80::…) — no global IPv6. That suggests the host bridge isn’t getting or relaying a global IPv6, so containers won’t have an upstream path.

Can you check vmbr0 has a proper global IPv6 + default route, and that IPv6 forwarding / bridging is not blocked by firewall settings?