0.0.0.0
Encyclopedia
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
.
Uses include:
To give a special meaning to an otherwise invalid piece of data is an application of in-band signaling
In-band signaling
In telecommunications, in-band signaling is the sending of metadata and control information in the same band or channel used for data.-Telephone:...
.
Uses include:
- The address a host claims as its own when it has not yet been assigned an address. Such as when sending the initial DHCPDISCOVER packet when using DHCP.
- The address a host assigned to itself when address request via DHCP have failed. This usage has been replaced with the APIPA mechanism in modern operating systems.
- A way to specify "any IPv4-host at all". It is used in this way when specifying a default routeDefault routeA default route, also known as the gateway of last resort, is the network route used by a router when no other known route exists for a given IP packet's destination address. All the packets for destinations not known by the router's routing table are sent to the default route...
. - A way to explicitly specify that the target is unavailable.
- A way to specify "any IPv4-interface at all". It is used in this way when configuring the Apache webserver.