Forwarding Multicast Traffic

Forwarding Multicast Traffic

[ms419]

Two machines communicate with one another using multicast - mDNS - when 
they are on the same network segment. When they are on separate network 
segments, however - though they can connect to one another across a 
router - they can't communicate using multicast. I presume that this is 
because the router isn't forwarding multicast traffic to other network 
segments? The router is running Linux kernel version 2.4.23 and 
iptables. How can I configure iptables to forward multicast traffic to 
other network segments?

Thanks very much,

Jack

Re: Forwarding Multicast Traffic

[Ray Leach]

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On Mon, 2004-02-09 at 09:31, ms419@freezone.co.uk wrote:
> Two machines communicate with one another using multicast - mDNS - when 
> they are on the same network segment. When they are on separate network 
> segments, however - though they can connect to one another across a 
> router - they can't communicate using multicast. I presume that this is 
> because the router isn't forwarding multicast traffic to other network 
> segments? The router is running Linux kernel version 2.4.23 and 
> iptables. How can I configure iptables to forward multicast traffic to 
> other network segments?
> 
Make sure you have the appropriate FORWARD and -t nat PREROUTING (if you
use NAT) rules to forward the multicast traffic (224.0.0.0)

> Thanks very much,
> 
> Jack
-- 
--
Raymond Leach <raymondl@knowledgefactory.co.za>
Network Support Specialist
http://www.knowledgefactory.co.za
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RE: Forwarding Multicast Traffic

[Sebastian]

Hi there...

As you said multicast traffic is normaly not routed. But you can do a
view steps to do this. First enable multicast support and multicast
routing in the routers linux kernel. I've tried to route multicast
packets with the iptables -j ROUTE target IIRC, but that doesn't seem to
work. The much cleaner is to use the multicast routing daemon (mrouted).
On debian systems you can easily apt-get the packet, on other systems i
suggest to google around.

Greets
  Basti.


> -----Original Message-----
> From: netfilter-admin@lists.netfilter.org 
> [mailto:netfilter-admin@lists.netfilter.org] On Behalf Of 
> ms419@freezone.co.uk
> Sent: Monday, February 09, 2004 8:31 AM
> To: netfilter@lists.netfilter.org
> Subject: Forwarding Multicast Traffic
> 
> 
> Two machines communicate with one another using multicast - 
> mDNS - when 
> they are on the same network segment. When they are on 
> separate network 
> segments, however - though they can connect to one another across a 
> router - they can't communicate using multicast. I presume 
> that this is 
> because the router isn't forwarding multicast traffic to 
> other network 
> segments? The router is running Linux kernel version 2.4.23 and 
> iptables. How can I configure iptables to forward multicast 
> traffic to 
> other network segments?
> 
> Thanks very much,
> 
> Jack
> 
> 
> 

Re: Forwarding Multicast Traffic

[hclfm]

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