Anybody can answer my question regarding multicast routing.

i have read Linux 2.4 Advanced Routing HOWTO and i have some
question about multicast routing.

I have two network to route between. Can you give me some tips to
configure the routing table.

I have two LAN connecting each other through Linux Box.
Box A
eth0 : internet Add
eth1 : local subnet (192.168.0.0)

Box B
eth0 : 192.168.0.15
eth1 : 10.100.0.1

Client C (windows 98) connect to Box B is 10.100.0.10

How can my Client C can send multicast packet to LAN connected to BOX A and
B in the same time (sending from client C 10.100.0.10)?I
use IP Masquerade to make sure my "Client C" can connected directly to
internet. same as i use it at BOX A and B.

I can send multicast packet from Client C to Box B, and Box B to Box A. But
can't send from Client C to Box A. Box A can
send multicast packet to Box B  but can't send to Client C.

I think may be i have to configure the multicast routing at BOX B. But I
have tried many ways but failed.

Thank you.

ps: sorry for the bad english language.