' *ip multicast helper-map' *converts broadcast traffic to multicast traffic to be sent across a multicast capable network and then turned back to broadcast...
i think you are wanting to change the multicast address and unicast it? not sure about that one? here is more info on ' *ip multicast helper-map'* http://blog.ine.com/2008/05/06/understanding-the-ip-multicast-helper-map-command/ http://www.cisco.com/en/US/docs/ios/ipmulti/command/reference/imc_03.html#wp1058167 -- Garry L. Baker "There is no 'patch' for stupidity." - www.sqlsecurity.com On Mon, Aug 2, 2010 at 4:30 PM, Johan <[email protected]> wrote: > Hi List > > I have an interesting case, I would like to route mDNS through 2 subnets. > > The topology is quite simple : > Network 172.16.0.0/16 > > HostA-----Fa0/0----R1------Fa0/1----HostB > 10.2 10.1 11.1 11.2 > > The communication doesn't have to be bi-directionnal, only from HostA to > HostB. > > As far as I know, mDNS uses 224.0.0.251 and the port UDP 5053. > > That said, this is a local-link multicast address and it will then no > traverse R1. > > My idea is like this > > Int fa0/0 > ip address 172.16.10.1 255.255.255.0 > ip multicast helper-map 224.0.0.251 172.16.11.1 100 > > > Int fa0/1 > ip address 172.16.11.1 255.255.255.0 > ip multicast helper-map broadcast 224.0.0.251 100 > > access-list 100 permit udp any any eq 5053 > > Could you confirm my understanding of ip multicast helper-map ? or > point me where I am wrong ? > > On fa0/0, R1 will convert the multicast received on 224.0.0.251 and > forward it to fa0/1 as broadcast. > On fa0/1, R1 will reconvert it as multicast and forward the packet to > the other segment. > > thanks ! > > Johan > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com >
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