Jun 2017

To show if an interface is actively listening to any multicast streams, we can show this by using the netstat command:

netstat -ng

IPv6/IPv4 Group Memberships
Interface       RefCnt Group
--------------- ------ ---------------------
lo              1      224.0.0.1
eth2            4      239.0.200.1
eth2            1      224.0.0.1
eth3            1      224.0.0.1
eth4            1      224.0.0.1
eth5            1      224.0.0.1
eth0            1      224.0.0.1
eth1            1      224.0.0.1
lo              1      ff02::1
eth2            1      ff02::1
eth3            1      ff02::1
eth4            1      ff02::1
eth5            1      ff02::1
eth0            1      ff02::1
eth1            1      ff02::1

This is a packager (v8) that I have setup a service on. That service is an ABR service containing four streams, so the line:

eth2 4 239.0.200.1
Is interesting to me, I can see that from address 239.0.200.1 (the MFEL multicast output) Interface 2 is connected to four multicasts.