Basics - network and server

Catalog

Server and client

Services provided by the server

Server software

Network related knowledge concepts

IP Address

domain name

DNS Domain name resolution server

port

Communication protocol

Server and client

Both the server and the client are computers , The differences between them are as follows ：

Conceptual differences ：

The server ： A computer that can provide a service

client ： Computers that want to use the services provided by the server

Hardware differences ：

The server ： Because we need to provide services for many clients , The hardware configuration of the server should be higher

client ： Personal computer 、 mobile phone 、 Tablets and so on can be called clients

Be careful ：

There is no obvious division between server and client on the hardware level , Computers with poor configuration can still be used as servers , It's just that this server is slow .

Services provided by the server

Functions often used in our daily life , All services provided by the server , for example ： Web Services 、 mailbox service 、 File upload and download service 、 Chat service and so on ......

Server software

Since the server is also a computer , Then this computer must be installed with an operating system , Otherwise, it's a naked machine , Nothing can be done , Not to mention providing services . Generally speaking , More servers will choose Linux operating system , Personal computers are more likely to choose to install Windows operating system .

The server can provide services because a lot of software is installed on the server operating system , These software provide external services , such as :

HTTP Web Services ：Apache、 Tomcat、lIs etc. .

File upload and download service ：VsFtp etc.

mailbox service ：SendMail etc. .

Data storage services ：MySql、Oracle etc. .

summary ： The server provides services , The client uses the services provided by the server .

Network related knowledge concepts

IP Address

The address is to mark a place , Easy to find . Many companies on the Internet , Each company has its own server to provide services . adopt ip Address can find a specific server , Using the services provided by this server .

For example, Baidu's ip The address is ：202.108.22.5

domain name

because IP The address is a string of numbers , It's hard to remember . It's like latitude and longitude , What people can remember is place names . And the domain name is equivalent to the place name , Convenient for people to find the server .

For example, the website ：www.baidu.com www.qq.com

View the native IP( Win + R Input cmd )：ipconfig （ip The address is Lan ip It's not a WAN ip Address ）

View the IP： ping www.qq.com

DNS Domain name resolution server

DNS It's called domain name resolution server , Provide domain name and ip Address mapping .

The process of accessing the server ： This machine hosts file -->DNS The server --> The server

This machine host The path of the file is ：c:\Windows\System32\drivers\etc\HOSTS

port

We said earlier , The server provides services .ip Address is used to find a server . Domain name is convenient for people to remember .DNS Is to maintain the domain name and ip Mapping of addresses . So you can find a server through the domain name , We can really find a server through the domain name , But one server can provide many services , When we found this server , What service do you want to use on this server ?

This is distinguished by the port number , Actually, every time we visit the website , The most complete way of writing should be http://www.baidu.com:80 ,80 This port is special , You can omit it . therefore Ports are used to distinguish between different services provided on the server .

summary ： ip Address is used to find a server . Domain name is convenient for people to remember .DNS Maintain the domain name and ip Address mapping . Ports are used to distinguish between different services provided on a server .

Communication protocol

A communication protocol is a predetermined rule . The protocol can be simply thought of as what two computers say when they communicate .

Common protocols :

HTTP、HTTPS： Hypertext transfer protocol

FTP： Text transfer protocol

SMTP： Simple mail transfer protocol

stay HTTP Agreement , What we need to know roughly is ： Request header 、 Response head 、 Request body 、 Response body .

The computer world is full of various protocols , Any kind of agreement is to stipulate some specifications , For the agreement itself , The content inside is quite complicated , We don't need to delve into .