Network communication learning

Network communication overview

The purpose of using the Internet

Purpose ： Resource sharing
Constituent unit ： Multiple independent stations distributed in different geographical locations “ Autonomous computer ”
Network protocol
Using the network, you can connect many parties together , And then data communication
Network programming is - Let software on different computers be able to transmit data , That is, communication between processes
IP Address ： Used to mark a computer on the network

see ip Address

linuxifconfig
windows ipconfig
Close network card ifconfig eth0 down
Open network card ifconfig etn0 up

ipv4 and ipv6

When ipv4 When it's not enough ,ipv6 There is a
ip Address classification ： Classify according to the host address , There are three categories
ip The size of the address ：255:255:255:255
xxx.xxx.xxx: network address
xx: Host number
Current network number ：xxx.xxx

Broadcast address

unicast
multicast

port

End to end data transmission , use ip
The program on the end sends data to the application of another machine ip+port