IP multicast is a set of protocols that network appliances use to send multicast IP datagrams to a group of interested receivers using one transmission rather than unicasting the traffic to multiple receivers, thereby saving bandwidth. IP multicast is suitable for communication from one source (or many sources) to many receivers, such as audio or video streaming, IPTV, video conferencing, and distribution of other communication, such as news and financial data.

A multicast address identifies a group of receivers that want to receive the traffic going to that address. You should not use the multicast addresses reserved for special uses, such as the range 224.0.0.0 through 224.0.0.255 or 239.0.0.0 through 239.255.255.255. Multicast traffic uses UDP, which does not resend missed packets.

Palo Alto Networks® firewalls support IP multicast and Protocol Independent Multicast (PIM) on a Layer 3 interface that you configure for a virtual router on the firewall.

For multicast routing, the Layer 3 interface type can be Ethernet, Aggregate Ethernet (AE), VLAN, loopback, or tunnel. Interface groups allow you to configure more than one firewall interface at a time with the same Internet Group Management Protocol (IGMP) and PIM parameters, and with the same group permissions (multicast groups allowed to accept traffic from any source or from only a specific source). An interface can belong to only one interface group.

The firewall supports IPv4 multicast—it does not support IPv6 multicast. The firewall also does not support PIM Dense Mode (PIM-DM), IGMP proxy, IGMP static joins, Anycast RP, GRE, or multicast configurations on a Layer 2 or virtual wire interface type. However, a virtual wire interface can pass multicast packets. Also, a Layer 2 interface can switch Layer 3 IPv4 multicast packets between different VLANs and the firewall will retag the VLAN ID using the VLAN ID of the egress interface.

You must enable multicast for a virtual router and enable PIM for an ingress and an egress interface in order for the interfaces to receive or forward multicast packets. In addition to PIM, you must also enable IGMP on egress interfaces that face receivers. You must configure a Security policy rule to allow IP multicast traffic to a predefined Layer 3 destination zone named

multicast

or to

any

destination zone.