Part ONE: Protocol levels and their service types

OSI seven layer model

TCP/IP reference model

TCP/IP five-tier reference model

Comparison of OSI model and TCP/IP model

OSI and TCP/IP protocols

Why did TCP/IP remove the presentation and session layers

How data is transferred between layers [Data encapsulation process]

Part two: Application layer

What information the HTTP header contains

Keep-alive is different from non-keep-alive. Does it affect server performance

What are the application scenarios of HTTP long connection short connection

How do I know the length of an HTTP packet

HTTP methods know what

GET and POST

What’s the limit on the length of GET

How HTTP and HTTPs work

The difference between HTTPS and HTTP

HTTPS encryption mode

Why do clients trust third-party certificates

HTTP is a protocol that does not save state. How to save user state

Status code

Differences between HTTP/1.1 and HTTP/1.0

The difference between HTTP/ 1.x and HTTP/2.0

HTTP / 3 understand

The functions and principles of DNS

DNS 为什么用 UDP

How to implement DNS hijacking

Socket () Which sockets are available

The difference between a URI (Uniform Resource Identifier) and a URL (Uniform resource Locator)

Why did Fidder Charles catch your packet?

If you visit a website slowly, how to troubleshoot and solve

Other agreements

The whole process of web page parsing [the whole process of the user entering the URL to display the corresponding page]

Part three: Transport layer

Three-way handshake and four-way wave mechanism

What happens when you shake hands three times and each handshake message is not received

Why three handshakes? Can I shake hands twice?

The second handshake returns AN ACK. Why should it return a SYN

Why do you wave four times?

The status and significance of close-wait and time-wait

What problems can BE caused by TIME_WAIT state and how can I solve them

Time-wait: 2MSL

If there are many time-wait states, how to solve them

How to solve close-wait problem when there are many close-wait problems

Differences between TCP and UDP

TCP timer

How does TCP ensure reliability

Why is UDP unreliable? What do bind and connect do for UDP

Mechanism of TCP timeout retransmission

What is TCP’s stop-wait protocol

Maximum number of TCP connections

TCP traffic control and congestion control

What does the sender do if the receiver’s sliding window is full

TCP congestion control adopts four algorithms

TCP sticky packet problem

The information contained in TCP packets

What is SYN FLOOD

Why is the server vulnerable to SYN attacks

The difference between a high concurrency server and a client actively closing a connection

Part four: Network layer

Definition and functions of the IP protocol

Can one IP address correspond to multiple domain names

How to solve the problem that IPV4 addresses are insufficient

Packet forwarding process of the router

The difference between routers and switches

ICMP Concepts and Functions

The application of ICMP

What problems do you think may exist when two computers cannot ping when they are connected?

This section describes the principle and process of ARP address resolution

Network address translation NAT

What is TTL? What does it do

The difference between transport layer protocols and network layer protocols

Part five: Data link layer

What are MAC addresses and IP addresses used for

Why do I need an IP address when I have a MAC address

Why do YOU need a MAC address when you have an IP address

Conversion between a private IP address and a public IP address: Are the two private IP addresses on the same LAN the same

CSMA/CD protocol in Ethernet

Three basic problems at the data link layer

The PPP protocol

Why PPP protocol does not use serial number and confirmation mechanism

Part six: The Physical Layer

What does the physical layer do

Communication between hosts

Channel multiplexing technology

Several commonly used broadband access technologies

Part seven: Security in computer networks

What are the security attacks

ARP attack

Symmetric encryption and asymmetric difference, asymmetric encryption what

The process of AES

What is the difference between RSA and AES

What are DDoS attacks and how can I defend against them