IP address detailed explanation

IP address

Check the IP address: ipconfig / all to view the details of the local computer address

IP address: 192.168.25.13

Subnet mask: 255.255.255.0

Gateway: 192.168.25.1

DNS:61.139.2.69

What is the IP address?

The IP address is a location of the computer in the network

The location identified by a computer in the network is represented by an IP address

Third, the representation of the IP address:

IP addresses are identified in dotted decimal, four bytes and 32 bits

Bit: a binary tree

Byte: octet binary represents a byte

8bit=1byte

4. IP address

Highest IP address:

255.255.255.255

Lowest IP address:

0.0.0.0

IP address classification:

1. Class A: the first byte is 1-126 (big net)

2. Class B: the first byte is 128-191.

3. Class C: the first byte is 192-223 (small net)

4. Class D: the first byte is in 224-239 (multicast)

5. Class E: the first byte is 240-255 (scientific research)

Note: the first byte is the loop return address, in order to test the perfect match between the TCP/IP protocol and the computer system.

5. Private network scope of IP address:

Category A: 10.0.0.0-10.255.255.255

Category B: 172.16.0.0-172.31.255.255

Class C: 192.168.0.0-192.168.255.255

6. Subnet mask:

The main function of subnet mask is to identify the network bits and host bits of a computer in the network.

It consists of all one, identifies the network bit, and all zero constitutes the identification host bit.

Default subnet mask:

Category A: 255.0.0.0

Category B: 255.255.0.0

Class C: 255.255.255.0

7. Subnetting:

IP address: 192.168.2.0

Subnet mask: 255.255.255.0

11111111.111111111111111111.00000000 (divide the subnet mask into dotted binary)

Number of subnets: (find bytes where 0 and 1 coexist, if there is any, 2 ^ 1 = 2 [write → if not found]) 2 ^ 0 = 1

Number of hosts: (number of zeros) 2 ^ 8 = 256

Number of valid hosts: (number of hosts-2) 256-2cm 254 (the first host cannot be used, and the last host cannot use SO-2)

Number of segments: (fixed value 256 divided by number of subnets)

Subnet range: subnet mask binary, one to one corresponding to 192.168.2.0-192.168.2.255

Valid subnet range: 192.168.2.1-192.168.2.254