Linux Network Basics network IP note

I. Class A address starts with 0 and 10000 is A private address Class B address

I. Class A address starts with 0 and 10.0.0.0 is A private address.

Class B address starting with 10, 172.16.0.0 ~ 172.31.255.254 is a private address.

Class C address starting with 110, 192.168.0.0 ~ 192.168.255.254 is a private address.

Host address 127. X

2. subnet mask, network address, and broadcast address conversion.

256 minus the number of the non-255 and 0 parts of the subnet mask to obtain the network number difference of the divided subnet. The bitwise of the subnet mask corresponds to the position of the network number. The broadcast address is the lower-layer network number minus the broadcast address of the upper-layer network.

172.16.1.0/25 subnet mask ----- 255.255.255.255.128

/26 ------ maximum bandwidth limit 192

/27 minutes later than expected

/28 ---- 255.255.255.255.240

/29 ---- 255.255.255.248

/30 ---- 255.255.255.252

/31 255.255.255.254

To find the network number and broadcast address, follow these steps:

1: first obtain the subnet mask

2: use 256 minus the subnet mask to get the network number difference. pay attention to the corresponding bit.

3: obtain the network number.

4: The upper-layer network number is reduced to the lower-layer broadcast address.