The destination address of the multicast packet uses the class d IP address,
The range is from 224.0.0.0 to 239.255.255.255. Class d addresses cannot appear in the source ip address field of an ip packet.
224.0.0.0 to 224.0.0.255 are reserved multicast addresses (permanent group addresses), which can only be used in local area networks and are not forwarded by routers.
224.0.0.0 is reserved for allocation, and other addresses are used by routing protocols.
224.0.1.0～238.255.255.255 are multicast addresses (temporary group addresses) available to users, which can be used on the Internet.
239.0.0.0～239.255.255.255 are local management multicast addresses, which are only valid in a specific local range.