Andrisoft Wanguard 5.2, Руководство пользователя и администратора, Страница: 62 / 73

WANGUARD 5.2 User Manual & Administrator's Guide
IP Classes
Class A addresses always have the frst bit of their IP addresses set to “0”. Since Class A networks have an 8-
bit network mask, the use of a leading zero leaves only 7 bits for the network porton of the address, allowing for a
maximum of 128 possible network numbers, ranging from 0.0.0.0 – 127.0.0.0. Number 127.x.x.x is reserved for
loopback, used for internal testng on the local machine.
Class B addresses always have the frst bit set to “1” and their second bit set to “0”. Since Class B addresses
have a 16-bit network mask, the use of a leading “10” bit-patern leaves 14 bits for the network porton of the
address, allowing for a maximum of 16,384 networks, ranging from 128.0.0.0 – 181.255.0.0.
Class C addresses have their frst two bits set to “1” and their third bit set to “0”. Since Class C addresses
have a 24-bit network mask, this leaves 21 bits for the network porton of the address, allowing for a maximum of
2,097,152 network addresses, ranging from 192.0.0.0 – 223.255.255.0.
Class D addresses are used for multcastng applicatons. Class D addresses have their frst three bits set to
“1” and their fourth bit set to “0”. Class D addresses are 32-bit network addresses, meaning that all the values within
the range of 224.0.0.0 – 239.255.255.255 are used to uniquely identfy multcast groups. There are no host addresses
within the Class D address space, since all the hosts within a group share the group’s IP address for receiver
purposes.
Class E addresses are defned as experimental and are reserved for future testng purposes. They have never
been documented or utlized in a standard way.
WANGUARD uses extensively, throughout its components, IP Addresses and IP Classes with the CIDR
notaton.
- 61 -