
2-48
Cisco PIX Firewall and VPN Configuration Guide
78-15033-01
Chapter 2 Establishing Connectivity
Enabling Stub Multicast Routing
Example 2-7 Inside Receiving Hosts with Access Control
The following example configures the inside and DMZ receivers:
multicast interface outside
igmp access-group 1
multicast interface inside
igmp forward interface outside
igmp access-group 1
multicast interface dmz
igmp forward interface outside
igmp access-group 1
! The following permits igmp messages to 225.2.1.0/25 network
access-list 1 permit igmp any 225.2.1.0 255.255.255.128
access-list 1 deny ip any any
! The following permits multicast packets in the network 225.2.1.0/25 in the
! outside interface of the PIX
access-list 100 permit udp any 225.2.1.0 255.255.255.128
access-list 100 in interface outside
Forwarding Multicasts from a Transmission Source
When a multicast transmission source is on the inside (or more secure) interface of a PIX Firewall, you
must configure the PIX
Firewall to enable multicast forwarding from the source. You enable multicast
forwarding on the PIX
Firewall interfaces towards each network containing hosts that are registered to
receive multicast transmissions from the source.
To configure the PIX Firewall to forward multicast transmissions from a source, perform the following
steps:
Step 1 Enable multicast forwarding on each PIX Firewall interface by entering the following command:
multicast interface interface-name
This command enables multicast support on the specified interface and places the interface in multicast
promiscuous mode. When you enter this command, the CLI enters multicast subcommand mode and the
prompt changes to identify the interface you are configuring.
To use this command:
• Replace interface-name with the name of the PIX Firewall interface on which you wish to enable
multicast forwarding.
Step 2 Create a static route from the transmission source to the next-hop router interface:
[no] mroute src smask in-if-name dst dmask out-if-name
• Replace src and smask with the IP address and subnet mask of the multicast source.
• Replace in-if-name with the name of the PIX Firewall interface connected to the multicast source.
This is typically the inside (or more secure) interface.
• Replace dst and dmask with the Class D address and subnet mask for the multicast transmission from
the source.
Comentarios a estos manuales