IP multicast addresses are mapped to a reserved set of Media Access Control multicast addresses and assigned from within the Class D address range from 224.0.0.0 throug 239.255.255.255. A single IP address within the reserved range identifies each multicast group. Each multicast group IP address is shared by all host members of the group who listen and receive any IP messages sent to the group IP address.
The following table is a partial list of Class D addresses reserved for IP multicasting and registered with the Internet Assigned Numbers Authority (IANA).
Multicast group |
IP multicast address |
Description |
| Base address | 224.0.0.0 | Reserved |
| All hosts | 224.0.0.1 | Contains all systems on the same physical network |
| All routers | 224.0.0.2 | Contains all routers on the same physical network |
| Network Time Protocol | 224.0.1.1 | Distributes time-clock data used to synchronize time on a group of computers |
| RIP version 2 | 224.0.0.9 | Distributes routing data between a group of routers that use a version 2 raster image processor (RIP) |
| WINS server | 224.0.1.24 | Supports autodiscovery and dynamic configuring of replication for WINS servers |