Page 766 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

administrators the ability to group and then block or allow access

to network services, such as file servers or printing.
Autoconfiguration removes the need for both Dynamic Host
Configuration Protocol (DHCP) and Network Address Translation
(NAT). QoS priority values allow for traffic management based on
prioritized content.

IPv6 is supported by most operating systems released since 2000,
either natively or via an add-in. However, IPv6 has been slowly

adopted. Most of the IPv6 networks are currently located in private
networks such as those in large corporations, research
laboratories, and universities. For a glimpse into the status of IPv4
to IPv6 conversion on the internet, see the IPv6 statistics at
https://www.google.com/intl/en/ipv6/statistics.html.

IP classes

Basic knowledge of IP addressing and IP classes is a must for any
security professional. If you are rusty on addressing, subnetting,
classes, and other related topics, take the time to refresh yourself.

Table 11.3 and Table 11.4 provide a quick overview of the key details of
classes and default subnets. A full Class A subnet supports 16,777,214
hosts; a full class B subnet supports 65,534 hosts; and a full Class C
subnet supports 254 hosts. Class D is used for multicasting, while
Class E is reserved for future use.

TABLE 11.3 IP classes

Class First binary digits Decimal range of first octet

A 0 1–126

B 10 128–191

C 110 192–223
D 1110 224–239

E 1111 240–255

TABLE 11.4 IP classes’ default subnet masks