sending multicast in Linux

[wkevin]

Hello,
Can someone suggest some tool to send multicast in Linux?

when I try to set an iperf server with iperf -s -u -B 224.0.55.55
I get:

>multicast join failed: No such device

even though there **is** 224.0.55.55 on eth0, as netstat -g shows.

I don't know what the problem here.

I will appreciate if someone can suggest another tool

Rgs
Kevin

[wkevin]

Hi,
strangely it was I solved when I added default gw .... not sure why

[Jorgen Grahn]

I know little about multicast apart from what ip(7) says, but it seems
rather likely that the tool works and it reports an actual error.

Try running strace on it to see what system call fails with ENODEV.
Also check the syslog for complaints from the kernel.

/Jorgen

--
// Jorgen Grahn <grahn@ Oo o. . .
\X/ snipabacken.se> O o .

[Andy Furniss]

wkevin wrote:
> Hi,
> strangely it was I solved when I added default gw .... not sure why

I can't claim to know much about multicast, but from doing the bare
minimum in the past to get something working - yes it needs a route and
default will do.

You could explicitly add one

ip route add 224.0.0.0/4 dev XXX

Which of course you need to do in the case of multiple ifs one with
default where you don't want locally generated multicast to use the default.

To do multicast routing you need to install and configure something for
the task.