Linux network based network IP notes

One: Class A address 0 starts with 10.0.0.0 as private address

Class B address starts with 10, and 172.16.0.0~172.31.255.254 is private address

C class address 110 starts with 192.168.0.0~192.168.255.254 is a private address

Local address 127.XXX

2: Subnet mask, network address, broadcast address conversion.

256 subtracts the number of the subnet mask other than 255 and 0, and obtains the difference between the network numbers of the subnets that are divided. The subnet mask is decremented corresponding to the location of the network number. The broadcast address is the lower layer network number minus one to get the broadcast address of the upper layer network.

172.16.1.0/25 Subnet Mask-----255.255.255.128

/26 ------255.255.255.192

/27 255.255. 255.224

/28 ----255.255.255.240

/29 ---- 255.255.255.248

/30 ---- 255.255.255.252

/31 255.255.255.254

To find the network number and broadcast address:

1 : Find the subnet mask first

2: Subtract 256 The netmask gets the difference between the network numbers, paying attention to the corresponding bits.

3: Get the network number.

4: The upper layer network number is decremented by one to get the lower layer broadcast address.