R1#sh run | b 0/0
interface Ethernet0/0
 ip address 17.57.100.1 255.255.255.0
 ip pim sparse-dense-mode
 ip igmp access-group Prob6
 half-duplex
!
!
ip access-list standard Prob6
 deny   224.20.73.1 15.128.20.0
 permit any
!