Multicast Routing - Part III Controlling Access

If there is a requirement to restrict multicast groups that hosts on a segment can join this can be achieved by filtering on the connected interface.

Simplying create an acl denoting those multicast groups that are permitted on the LAN segment. Then apply the 'ip igmp access-group {acl}' command to the interface.

For example, i restrict access to multicast groups 227.20.20.20 and 228.20.20.20 on the interface as follows

access-list 60 permit 227.20.20.20
access-list 60 permit 228.20.20.20

#int fa0/23
config-if#ip igmp access-group 60

To check the acl has been appiled i use 'show ip igmp interface fa0/23' command.