What is the multicast address for "All nodes" in IPv4?

The multicast address for "All nodes" in IPv4 is specifically defined as 224.0.0.1. This special multicast address is used to reach all IP nodes on a local network segment. When a device sends a packet to this address, all hosts that are part of that network and are configured to listen for such multicast traffic will receive the packet.

The use of this particular address is significant in network protocols and services that benefit from notifications or data being sent to multiple nodes at once, such as routing protocols and certain applications. The other options represent different multicast addresses that have specific functions or targeted groups and are not intended to be used for broadcasting to all nodes. Thus, 224.0.0.1 is the recognized standard for broadcasting messages to all hosts within a local network.