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
