multicast issue (both subscriber and send)

I am trying to setup a multicast subscriber to join some multicast groups hops away (publisher is from different broadcast domain of subscriber).

at first it does not work at all but after manually added a route to publisher’s network it works.

I have tried from redhat and some windows boxes, at the same time and neither of them need to know publisher’s network in order to subscribe to the multicast group.

Any hint?

Thanks,

i’d guess the routers/switches between your hops need to agree to forward multicast group traffic.