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Forwarding specific udp broadcasts between ip networks

Hello all,

I'm trying determine what would be the best way to forward some specific udp broadcast traffic from one subnet to another and vice versa on the same router. I can't use ip helper because it is already configured to enable dhcp traffic and I do not want this particular udp traffic forwarded all the way across my network to the dhcp server as a by product of getting where it needs to go.

The network elements generating this traffic for example, address their broadcasts to with a hardware address of all FF. I need to route this traffic to be broadcast on a different interface/subnet on the same router so that the NEs on the two different IP networks can communicate with each other via these broadcasts. This is just needed as a temporary solution until all of the network elements can be moved onto the same subnet.

If I can't use ip-helper what is the path of least resistance to get this accomplished? Multi-cast helper perhaps? Can I use directed broadcast forwarding even though the broadcasts are addressed to their local IP subnet?

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Re: Forwarding specific udp broadcasts between ip networks


If you do not want to use ip helper-address then I do not believe that there is any router based solution for your problem. It might be possible to write something for some device on your network that would listen for these broadcasts, process them, and build broadcasts with destination address in the other subnet. But that would be an end station solution not a router solution.



Community Member

Re: Forwarding specific udp broadcasts between ip networks

Thanks Rick. That's kinda what I thought. Such are the joys of supporting lab environments.

Thanks for the taking the time to respond.

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