What is mean by 0.0.0.0 ip address?

Computers normally show an address of 0.0.0.0 when they are not connected to a TCP/IP network. Having this address, a computer cannot be reached or communicate with any other devices over IP.

TCP/IP software applications also use 0.0.0.0 as a programming technique to monitor network traffic from any valid IP address. While connected computers do not use this address, messages carried over IP sometimes include 0.0.0.0 inside the header when the source of the message is unknown.