Reserved IP Address belongs to the reserved IP address space - ( ). stands for this host on this network. It is used in device initialization when the final IP address is still unknown. Sometimes it is used as a means to indicate an error condition. Other usage includes static routes where is used to specify every possible IP address. Server processes like Apache webserver use or in its configuration to make them listen on any local IP address.

Not all IP addresses are available for public use, some of them were reserved by the Internet Engineering Task Force (IETF) and the Internet Assigned Numbers Authority (IANA) for special uses. One of these special purposes are private IP addresses that can be used by everyone in its local network without the need for prior allocation. The subnet was reserved for Local Identification in September 1981 as outlined in RFC 1122.

Hosts from this subnet are used to refer to a specified host on this network. These hosts are valid only as a source address during an initialization procedure where the final IP address is not yet known, for example during Dynamic Host Configuration Protocol (DHCP) setup. The class A network spans 16,777,216 ( 224 ) IP addresses ranging from to If you want to learn more about IP subnetting please take a look at our subnet calculator.

The address is sometimes misspelled, and you might see typical typing errors like these: 0.0.0.o, 0.0.o.0, 0.0.o.o, 0.o.0.0, 0.o.0.o, 0.o.o.0, 0.o.o.o, o.0.0.0, o.0.0.o, o.0.o.0, o.0.o.o, o.o.0.0, o.o.0.o, o.o.o.0, o.o.o.o

See also: IPv4 List - Page 3,138