What are the classifications of IP addresses?

IP address introduction:
Any device that can access the Internet must have an IP address;
And each IP address is equivalent to everyone must have a name;

Common IP addresses look like, such as the default address of TP-Link wireless routing:
192.168.1.1

Configure the IP address of your own network card:
192.168.1.2 255.255.255.0

Note:
The IP address must appear in pairs with the subnet mask, otherwise it is meaningless;

Check the IP address configuration of your own network card:
1. Through the graphical interface (click with the mouse )-That is, the win system
2. Through the command line
#Open the run, enter cmd, and call up the "command line window";
#Enter the command: ipconfig #
ipconfig /all-& gt; View all the network cards of the device
information;

Quickly call "Run" ----- start R;

---- -------------------------------------
Connectivity test tool - ping;
Working principle:
1. Send a "request packet" - request to the specified target IP address 2. The target device returns a "reply packet" - reply;

For example: ping successful!
PC>ping 192.168.1.2

Pinging 192.168.1.2 with 32 bytes of data:

Reply from 192.168.1.2: bytes=32 time=0ms TTL=128
Reply from 192.168.1.2: bytes=32 time=0ms TTL=128
Reply from 192.168.1.2: bytes=32 time=0ms TTL=128
Reply from 192.168.1.2: bytes=32 time=0ms TTL=128

Ping statistics for 192.168.1.2:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms

--------------------------------- -------------
For example: ping failed!
PC>ping 192.168.1.3

Pinging 192.168.1.3 with 32 bytes of data:

Request timed out. (The default timeout is 2s=2000ms)
Request timed out .
Request timed out.
Request timed out.

Ping statistics for 192.168.1.3:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

Shortcut command:
Press ctrl and c at the same time to quickly terminate the ping command;


Special ping command:
ping 127.0.0.1
This address represents the device itself;
#The command indicates that you send your data packet to yourself; , check whether the device's own network card/port
is functioning normally!

Classification of IP addresses: (x.x.x.x)
Goal: To facilitate the management of IP addresses;
Principle:
Look at the first few fixed bits of the first byte in the IP address;
0000 0000. 0000 ----> 0
0111 1111 ----> 127

B The first byte, the first 2 bits, if it is 10, it is called B
128-191 Default mask 255.255.0.0
1000 0000 --->128
1011 1111 --->191

C The first byte, in front 3 bits, if it is 110, it is called C
192-223 Default mask 255.255.255.0
D The first byte, the first 4 bits, if it is 1110, it is called D
224-239 No mask
E The remaining
240-255 are reserved for use in the laboratory. If you don’t understand this bit of IP address, you can leave it alone. Subnet mask It is also important to remember that the IP address and subnet mask must appear in pairs, this is very important! ! !

Class A address 0-127

Class B address 18-191

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