IP The address is a 32 The binary number of bits , Usually divided into 4 individual “8 Bit binary number ”（ That is to say 4 Bytes ）.IP The address is usually “ dotted decimal ” Expressed as （a.b.c.d） In the form of , among ,a,b,c,d All are 0~255 A decimal integer between .

A The range of class addresses is ：
0.0.0.0---127.255.255.255
use 32 The bit binary representation is ：
0000 0000.0000 0000.0000 0000.0000 0000---0111 1111.1111 1111.1111 1111.1111 1111
A Class address 32 The first digit of a binary is 0

B The range of class addresses is ：
128.0.0.0---191.255.255.255
use 32 The bit binary representation is ：
1000 0000.0000 0000.0000 0000.0000 0000---1011 1111.1111 1111.1111 1111.1111 1111
B Class address 32 The first two digits of a binary are 10

C The range of class addresses is ：
192.0.0.0---223.255.255.255
use 32 The bit binary representation is ：
1100 0000.0000 0000.0000 0000.0000 0000---1101 1111.1111 1111.1111 1111.1111 1111
C Class address 32 The first three digits of a binary are 110

Public address , from Inter NIC（Internet Network Information Center Internet Information Center bai） be responsible for . these IP The address is assigned to the register and to Inter NIC The organization making the application . Access the Internet directly through it .
private IP The address is used in the LAN IP Address . private IP The address is reserved for a paragraph IP Address . Only in LAN , Cannot be in Internet Upper use .
When a host in a private network wants to communicate with a host on a public network, it must undergo address translation , The private address can be converted into a legal public address in order to access to the outside world .

A class IP The first set of addresses is the network part , The last three groups are the host part ;
B class IP The first two groups of addresses are the network part , The last two digits are the host part ;
C class IP The first three groups of addresses are the network part , The last group is the host part .
Only the network part IP The same computer talent ping through .

Within the network scope of each category , All hosts are 0 Not available , Represents a network segment , Host bit binary is all 1 It can't be used , Represents a broadcast address .

A class IP Segment of address ：
10.1.1.1 255.0.0.0
The network segment is ：10.0.0.0
B class IP Segment of address ：
172.16.1.1 255.255.0.0
The network segment is ：172.16.0.0
C class IP Segment of address ：
192.168.1.1 255.255.255.0
The network segment is ：192.168.1.0
IP The address and subnet mask are matched to get the segment