WAN, Multicast, Python and how to realise

[Heiko Wundram]

On Tue, 2003-05-27 at 08:53, Hoppert, Kai wrote:
> I tried to realise a Multicast about the Internet but it didn't works.
> In Lan it works without problems.

Multicast traffic won't be let through by your DSL-router, or at least
be blocked at the provider. Sending packets to all machines on the
Internet is something that people don't really want to do. :) (It'd make
all lines even more full than they are now...)

If you need multicast functionality, and have two distinct subnets you
want to connect, you can use GRE-tunnels, which allow multicast traffic
to be relayed to another router (which must have an open GRE-tunnel to
the host that sends it), thus making both subnets appear to be
connected. You'll have to explicitly enable multicast routing support in
the kernel (if you use Linux, for all other systems: I don't know. :))

Look at the IP-GRE howto on how to accomplish this, there's no other
way, I presume, as long as both machines are not connected to the same
ethernet-segment, or connected by multicast-friendly routers (which
providers are certainly not...).

Heiko.