PPP & Multicast

["Stephen A. Witt" <sawitt@electra.rsc.raytheon.com>]

I'm trying to figure out how to do multicast IP over PPP. More
specifically, how to get the MULTICAST interface flag set for a PPP
network interface. I searched through the mailing list archives and found
no direct answer to my question, but I did find numerous examples that had
been sent in of 'ifconfig' output that showed the MULTICAST flag being set
for a PPP interface. My expectation was that if multicast support was
compiled in to the kernel, then the network interfaces would have the
multicast flag set. My Ethernet interface has its multicast flag set for
instance. I've looked at the multicast and ppp howto's, read some code in
the kernel, read the net-3 howto, etc., looked through all the /etc/init.d
files for this and haven't been able to find anything.

I'm using kernel 2.0.36, with the following kernel options set:

Network firewalls: yes
Network aliasing:  yes
TCP/IP networking: yes
IP forwarding/gatewaying: yes
IP multicasting:   yes
IP firewalling:    yes
IP masquerading:   yes
IP tunneling:      yes
IP multicast routing: yes
 
  among others.

Can anyone give me a lead to investigate this?

Thanks...