mdns-repeater (zeroconf/bonjour) does not listen on IPv6

[tuxjz]

Describe the issue you are experiencing

mdns-repeater in hassio_multicast container does not listen to IPv6 mdns port 5353.

Previously opened issue in wrong repo: https://github.com/home-assistant/core/issues/48751

What is the used version of the Supervisor?

supervisor-2021.03.9

What type of installation are you running?

Home Assistant Supervised

Which operating system are you running on?

Debian

What is the version of your installed operating system?

10.9

What version of Home Assistant Core is installed?

core-2021.4.3

Steps to reproduce the issue

1. Configure host interface(s) with IPv6 addresses
2. Make sure zeroconf has IPv6 enabled (default config)
3. check if there is any *:5353 or [::]:5353 port binding # ss -pnul on standalone instalation, there is, on hass there isn't

Anything in the Supervisor logs that might be useful for us?

# Put your logs below this line
ss -tapnul |grep mdns
udp UNCONN 0 0 172.30.32.1%hassio:5353 0.0.0.0:* users:(("mdns-repeater",pid=2351,fd=5))
udp UNCONN 0 0 10.59.180.4%ens192:5353 0.0.0.0:* users:(("mdns-repeater",pid=2351,fd=4))
udp UNCONN 0 0 0.0.0.0:5353 0.0.0.0:* users:(("mdns-repeater",pid=2351,fd=3))

[tlm]

+1 this.

What is the appetite for taking a PR to change the container over to using avahi or similar?