mcfirst- tool to check whether you can receive a given multicast transmission.

It supports both ASM/SSM, and IPv4/IPv6. You run it specifying multicast group (and source if SSM) and port number. It will then run until it receives a single multicast packet, and tell you how long it took. Optionally you may specify how many packets and/or for how many seconds it shall run. If you specify how long to run, it will also tell you how many bits and packets per second were received. Mcfirst -h for more options.

root@linux:# mcfirst ff7e:230:2001:254:8000::1235 8000

and in debug mode
root@linux:# mcfirst ff7e:230:2001:254:8000::1235 8000 -v -t 1