Multicast addresses are special types of IP addresses used to send data to multiple devices simultaneously. Instead of sending individual copies of data to each device, a single multicast message can be sent to a group of devices that are interested in receiving that information. This is efficient for applications like streaming video or audio, where many users want the same content at the same time. In the Internet Protocol version 4 (IPv4), multicast addresses range from 224.0.0.0 to 239.255.255.255. Devices that want to receive multicast messages join a specific multicast group, allowing them to receive data sent to that address without needing to establish separate connections for each device.