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Computer network security knowledge point

2026-05-12 03:591980NameNetworking

Effective audit principles

Forms of threat to the database

Change

Damage

Steal

Data backup

Concept: data backup refers to the process of copying all or part of the data collection from the application host's hard disk or array to other storage media in order to prevent the loss of data as a result of a system error or system failure

Questions and answers on computer network security

Purpose: to enable rapid recovery of data in the event of a system data collapse and rapid resumption of system operations

Type of data backup

Cold backup: backup in closed database status

Hotbackup: backup under active database

Logical backup

Data backup policy

Full backup

Incremental backup

Different backup

Backup as required

Data recovery type

Total recovery

Restore individual files

Redirection recovery: restore backup file (data) to another different location or system let's go

Disaster management system

Disaster tolerance systems, including data and applications

Data tolerance technologies

The core technology is data reproduction in two main ways:

Synchronized data copy: local data copied to offsite in full sync

Offset data reproduction: local data lateral copy to offsite

Technologies involved in establishing disaster response backup systems

San (store area network) and nas (network additional storage)

Remote mirror technology

Speed technology

Virtual storage technology

(iv) password

Symmetric password system:

Concept: also known as the traditional key password, whose encryption key is the same or similar to that of which the other key is easily derived, so the encryption key is confidential

Algorithms: des, idea, tdea, aes

Characteristics: advantages such as ease of achievement, speed, interoperability, but also the low number of keys, low level of confidentiality and complex key management

Asymmetric password system:

Concept: also known as the open key password, which is different from the encryption key and the default key, one of which is difficult to draw from the other, usually one is open and the other is confidential

Questions and answers on computer network security

Algorithms: rsa, ecc, dsa, md5

Characteristics: key management has advantages such as simplicity, ease of digital signature and high reliability, but also disadvantages such as complexity of algorithms, slow speed of encryption/declassification and difficulty in achieving them with hardware

Network encryption

Chain encryption: transmitting data is only encrypted on the data chain layer

End-to-end encryption: transfer data to encrypt on the application layer

Difference between digital signature and key encryption:

Digital signatures use the sender's key pair, the sender encrypts the summary with its own private key, and the recipient decrypts the digital signature with the sender's public key, which is a multi-relationship

The key encryption decryption process uses the recipient's key pair, the sender's encryption with the recipient's public key, the recipient's private key decryption with its own, and the multi-team relationship

Network secure communication protocols

Ssl protocol: agreement to establish a safe link between the client and the server, widely used for authentication and encrypted data transmission between the web browser and the server. The main part is the protocol of recording and handshake

Ssh (security shell) protocols: safety authentication protocols based on application and transmission layers, consisting mainly of ssh transfer layer protocols, ssh user authentication protocols and ssh connection protocols, together achieve ssh security confidentiality mechanisms

Ipsec(ips) protocol: includes authentication agreement ah (also known as authentication header), sealing of security load agreement esp, key management agreement ike and some algorithms for network authentication and encryption

(v) cyber-attack technology

Firewall

Concept: firewall is a defence system that isolates access control strategies between local and external networks and is a set of security facilities consisting of hardware and software equipment

Insufficient:

Network bottlenecks

There's no way to prevent an information attack that bypasses the firewall

We can't protect ourselves from the virus

We can't prevent an attack from insiders

Features:

All network data streams between the intranet and the extranet must pass through the firewall

Only data that fits the security strategy can pass through the firewall

He has a very strong resistance

Technical:

Package filter technology

Agent service technology

State detection technology

Self-adaptation proxy technology

Virus

Characteristics of computer viruses: reproductive, contagious, destructive, hidden, latent, triggerable, derivative, unpredictable。

Characteristics of cyberviruses: speed of transmission, wide spread, difficulty of clearance, destructiveness, diversity of viruses。

Attack

Dos attack (denial of services)

Ddos attack (distributed denial of services attack): attack carried out during preparatory phase - >occupation of puppet - > implantation program - >

Spill-out attacks in the buffer zone: means that when computers fill data bits inside the buffer zone, they exceed the capacity of the buffer zone itself and the spill-out data are covered by legitimate data。

Vpn (vpn): remote access technology, with a public network set up for a dedicated network

Vlan (virtual lan): is a logical set of equipment and users

(vi) internet security

Internet fraud

Ip electronic fraud: impersonating the ip address of another host with a mainframe device

Arp electronic fraud: agreement to convert ip address to mac address

Dns e-deception: conversion of domain names and ip addresses (delysis)

Web electronic fraud

Web service using http protocol, default web service 80 end mouth

Two major agreements for the email service:

Simple mail transfer protocol smtp (simple mail transfer protocol): default occupancy of 25 ports to send mail

Post office protocol pop3 (post office protocol): occupancy of 110 ports for receiving mail

Questions and answers on computer network security

Shandong expedition network technology

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