[KLUG Members] multicast

[Bert]

Rusty Yonkers wrote:

>I have a system with 4 network segments that are connected with a
>single Linux firewall system... I need to get multicast info from one
>side of the system to the others.... I have done some research ... it
>seems like if the kernel is setup to support it (not sure if the
>stock SuSE 8.2 kernel is) then I might only have to put in a static
>route.  I read an article that stated that I simply needed to also
>put in ....
>....................... section below from article ........
>
>So far, so good. We've enabled multicasting. Now, we have to tell the
>Linux kernel to actually do something with it, so we can start
>routing. This means adding the Multicast virtual network to the router table:
>ip route add 224.0.0.0/4 dev eth0
>
Your'e only telling here that the 224 network can be reached at the 
segment attached to eth0. Are you sure that only a 4 bit netmask is 
right? It seems to me that it should be 20, giving you addresses from 
224.0.0.0 up to 239.255.255.255.

My multicast knowledge seems to be short here, so I don't know if you 
have to add lines to your firewall such as:
iptables -A FORWARD -i eth0 -s 224.0.0.0/20 -o eth1 -d 224.0.0.0/20
and
iptables -A FORWARD -i eth1 -s 224.0.0.0/20 -o eth0 -d 224.0.0.0/20

allowing 224.* traffic to travel between eth0 and eth1, but I think you 
have to do something here.


Bert.