Cisco ASA 5505 - Manual (Page 498)

26-6
Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter 26 Configuring Multicast Routing
Customizing Multicast Routing
Disabling IGMP on an Interface
You can disable IGMP on specific interfaces. This information is useful if you know that there are no
multicast hosts on a specific interface and you want to prevent the ASA from sending host query
messages on that interface.
To disable IGMP on an interface, enter the following command:
Note Only the no igmp command appears in the interface configuration.
Configuring IGMP Group Membership
You can configure the ASA to be a member of a multicast group. Configuring the ASA to join a multicast
group causes upstream routers to maintain multicast routing table information for that group and keep
the paths for that group active.
Note If you want to forward multicast packets for a specific group to an interface without the ASA accepting
those packets as part of the group, see the
“Configuring a Statically Joined IGMP Group” section on
page 26-6 .
To have the ASA join a multicast group, enter the following command:
Configuring a Statically Joined IGMP Group
Sometimes a group member cannot report its membership in the group because of some configuration,
or there may be no members of a group on the network segment. However, you still want multicast traffic
for that group to be sent to that network segment. You can have multicast traffic for that group sent to
the segment by configuring a statically joined IGMP group.
Enter the igmp static-group command. The ASA does not accept the multicast packets, but instead
forwards them to the specified interface.
To configure a statically joined multicast group on an interface,enter the following command:
Command Purpose
no igmp
Example:
hostname(config-if)# no igmp
Disables IGMP on an interface.
To reenable IGMP on an interface, use the igmp command.
Command Purpose
igmp join-group group-address
Example:
hostname(config-if)# igmp join-group
mcast-group
Configures the ASA to be a member of a multicast group.
The group-address argument is the IP address of the group.