ArticleSource:
Http://www.cppblog.com/prayer/archive/2009/01/06/71349.aspx
Generally, the IP address 0.0.0.0 in the network indicates the entire network, that is, all hosts in the network.
However, in some old software, they may use 0.0.0.0 as the broadcast address, that is, when they send broadcast packets, the target address is 0.0.0.0 instead of 255.255.255.255. Therefore, when the Protocol Analysis Software captures the host whose IP address is 0.0.0.0, it indicates that 0.0.0.0 is used as the broadcast address for communication on the network, rather than representing the entire network.
Note: 0.0.0.0 is basically deprecated as a broadcast address, and the current networkProgramOr the device generally does not use 0.0.0.0 as the broadcast address.
When 0.0.0.0 appears in the network, we need to check the source host of the packet and whether it is manually generated by some old software, or this packet is generated by some illegal attacks.