Page 909 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

conversions comes in handy when attempting to identify

obfuscated addresses. If you are rusty in this skill area, take
advantage of online conversion primers, such as at the following
location:

http://www.mathsisfun.com/binary-decimal-hexadecimal-
converter.html

The Loopback Address

Another IP address range that you should be careful not to confuse
with the private IP address ranges defined in RFC 1918 is the

loopback address. The loopback address is purely a software
entity. It is an IP address used to create a software interface that
connects to itself via TCP/IP. The loopback address allows for the
testing of local network settings in spite of missing, damaged, or
nonfunctional network hardware and related device drivers.
Technically, the entire 127.x.x.x network is reserved for loopback
use. However, only the 127.0.0.1 address is widely used.