A Guide To LOcalhost

An Introduction To 127.0.0.1

127.0.0.1 is an IP address utilized for a looplock network connection. What does this mean? If
a user tries to connect to this IP address, they will be sent back to their computer. The address
is also known as a localhost. The localhost is the computer.

How the Localhost Works

If the command is relayed to the localhost, you would be hooked up to the system where the
commands were sent out. For instance, suppose the computer is called "Joker". If you telnet
from the Joker computer to the localhost, a message will appear. It will attempt to hook up to
the localhost.

The localhost is employed in lieu of the computer hostname to be linked to. This IP address is
the most wisely used localhost address. However, you can actually use any IP address
provided it starts with 127. This means 127.*.*.* can be used as a localhost.

Establishing a connection with the loopback address is similar to creating a connection with
remote network computers. The only difference is you don't have to deal with network
interface hardware.

For this reason it is widely utilized by software developers. It is also used by system
administrators. It is often used for testing programs and apps. If the connection is IPv4, the
computer's loopback address will be the 127.*.*.*. The subnet mask is typically 255.0.0.0.

Internet RFC

This IP addresses 127.*.*.*. are defined in RFC 330 as Special-Use IPv4 Addresses. The
127.0.0.0/8 block is defined as the Net host loopback address. If a higher level protocol sends
a datagram anywhere in the block, it will be looped in the host. This is typically implemented
with the 127.0.0.1 / 32 for looplock. However, addresses in the block must not be visible
anywhere else in the network.

There is also a localhost IPv6 version. In RFC 3513, it is defined as Internet Protocol Version
6 (IPv6) Addressing Architecture::1/128.

More Information about the Localhost

In simple terms, the localhost means the computer. It is the hostname allocated loopback
network interface address. The name is likewise a domain name. This will help prevent
confusion with the hostname definition. In IPv6, the loopback IP address is ::1. The localhost
is stated when one would usually use the computer hostname. For instance, a browser using
an HTTP server to http://localhost will show the local website home page. This will be
possible if the server is set up properly to work the loopback interface.

The loopback address can also be used for linking up to a game server. It can also be used for
the various inter-process communications. This facts about 127.0.0.1 indicate how
fundamental and basic the localhost is to a system. That's why it is so crucial for network
administrators.

References:
http://en.wikipedia.org/wiki/Localhost
http://www.tech-faq.com/localhost.html
http://www.tech-faq.com/127-0-0-1.html
http://www.mightyguide.net/127-0-0-1.html
http://www.rolo.org/127-0-0-1.html

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