Localhost

:

In applications to talk to themselves if this is needed. If you are running a server, localhost will most likely open a page. [http://127.0.0.1]

Being able to communicate with one s local machine as though it were a remote machine is useful for the purposes of testing, and also to contact services (such as computer game servers) located on one s own machine that are expected to be remote.

= Related Specification of IETF =

IETF document Special-Use IPv4 Addresses (RFC 3330) describes the 127.0.0.0/8 as a reserved IPv4 address block for loopback.

This address block will not be allocated or assigned to any organization or ISP. Any packet with an address of this address block 127.0.0.0/8 cannot appear outside of a host system. Within a host system, the Loopback interface is normally assigned the address 127.0.0.1 with subnetwork mask 255.0.0.0 . This makes the routing table of the local system set with a routing entry of 127.0.0.0/8 , so that packets destined to any address of this 127.0.0.0/8 would be routed internally within the local system.

On the other hand, only one addressing architecture specification of RFC 3513.

In RFC 3513, the specification says: The loopback address must not be used as the source address in IPv6 packets that are sent outside of a single node. An IPv6 packet with a destination address of loopback must never be sent outside of a single node and must never be forwarded by an IPv6 router. A packet received on an interface with destination address of loopback must be dropped.

*RFC 3330: Special-Use IPv4 Addresses *RFC 3513: Internet Protocol Version 6 (IPv6) Addressing Architecture

= Humor =

A typical prank played on records, typically in form warez.example.net , that all resolve to 127.0.0.1 ([http://www.bofh.net/~koos/warez.html]).