How do I connect a sandbox to a bridge?

[crocket]

I created a bridge interface named br-tor. Tor runs a TransPort and a DNSPort on br-tor interface.

I even set up radvd on br-tor interface for SLAAC.

/etc/radvd-tor.conf

interface br-tor {
  AdvSendAdvert on;
  prefix ::/64 {
  };
  RDNSS fd0b:bfe1:38ad:1::1 {
  };
};

However, when I execute firejail --net=br-tor librewolf, I see

Warning: the network interface br-tor is not configured
Warning: Not enough information to configure an IP address for
   interface --net=br-tor

How can I fix this?

[crocket]

It turns out that firejail requires an IPv4 address from a bridge.

radvd is required for SLAAC. Without radvd, IPv6 address is not assigned automatically.
But, IPv6 address is not required for operation.

firejail doesn't get DNS resolver from radvd. I had to manually give it a DNS server with --dns.

firejail --net=br-tor --dns=fd0b:bfe1:38ad:1::1 librewolf

This works with radvd.

firejail --net=br-tor --dns=172.16.0.1 librewolf

This works with or without radvd.