In the Internet Protocol Version 4, the address 0.0.0.0 is a non-routable meta-address used to designate an invalid, unknown or non-applicable target.To give a special meaning to an otherwise invalid piece of data is an application of in-band signaling. In the context of servers, 0.0.0.0 means "all IPv4 addresses on the local machine". If a host has two IP addresses, 192.168.1.1 and 10.1.2.1, and a server running on the host listens on 0.0.0.0, it will be reachable at both of those IPs. Uses include: In IPv6, the all-zeros address is typically represented by "::".