Comment 46 for bug 447442

(In reply to comment #16)
>
> iptables -t nat -I POSTROUTING 1 -d 224.0.0.0/4 -s 129.168.122.0/24 -j ACCEPT

Surely you wanted to do s/129/192/ didn't you?

> iptables -t nat -L POSTROUTING -n -v
>
> Chain POSTROUTING (policy ACCEPT 64 packets, 4057 bytes)
> pkts bytes target prot opt in out source
> destination
> 0 0 ACCEPT all -- * * 129.168.122.0/24 224.0.0.0/4
> 0 0 MASQUERADE tcp -- * * 192.168.122.0/24 !192.168.122.0/24 masq ports: 1024-65535
> 0 0 MASQUERADE udp -- * * 192.168.122.0/24 !192.168.122.0/24 masq ports: 1024-65535
> 1 84 MASQUERADE all -- * * 192.168.122.0/24 !192.168.122.0/24
>
...
> My conclusion is that adding a rule here (for this kernel version at least)
> for multicast traffic makes no sense since it doesn't get invoked. Also see
> comment 12.

It probably would if the address in the rule were correct. It works here.

It should be noted that you probably want to add 226.0.0.0/8 to your ACCEPT list.