Shulou(Shulou.com)06/01 Report--

1. Network Foundation:

1.1Iron Triangle of IT Industry: os,web,sql should understand no matter which IT position it is.

1.2 Development of Iron Triangle: languages, data structure algorithms, data patterns

1.3Test Iron Triangle: requirements, build environment and design use cases, find bug location problem code

1.4 Operation and maintenance Iron Triangle: basic knowledge plus business and software use

1.5 functions: resource sharing, information transmission, load balancing, centralized management, security and reliability, distributed management

1.6 computer system = Software system + hardware system

Software system = underlying driver software + network operating system + application system

Hardware system = computer + communication processing equipment + communication transmission equipment + communication switching equipment

1.7 simple and commonly used network commands:

Check IP configuration: ipconfig-all under windows

Under linux is ifconfig.

Check the network connection: ping-n IP address

Check network status: netstats-na under windows | findstr 8080

Under linux is ls-a-d

2.OSI reference model, TCP/IP model

OSI:open system interconnection Open system Interconnection reference Model

TCP/IP:transfer control protocol/internet protocol Transmission Control / Internet Protocol

2.1 OSI seven-layer model

Physical layer: network card, mac address, repeater magnification

Data link layer: Ethernet, mac address, layer 2 switch

Network layer: IP protocol, ip address, router, layer 3 switch

Transport layer: ports, protocols, sending and receiving messages

Session layer: establish session, session ID

Presentation layer: encoding format, meaning

Application layer: functional application service

Common commands:

Tracert: trace routes, for example: tracert-d sq.ytesting.com

Arp: address resolution, ip resolution to mac

Rarp: inverse address resolution, mac resolution to ip

Network devices:

Network card: mac address 48bits, which is recorded in the rom of the network card and is the only identification number of the network card in the network. Its function is to convert the data in the software to the signals in the computer hardware for digital-analog and analog-to-digital conversion.

Adjust to demodulator: perform digital-to-analog or analog-to-digital conversion between data and signals in the telephone line

Switch: packet switching in the local area network (looking for mac). There are also some switches with simple routing function as layer 3 switches.

Router: find the correct network address quickly in the wide area network, and the routing algorithm determines the routing speed.

Common command: route /? Manually configure static routing tables

Netsh queries or modifies network configurations locally or remotely, such as netsh interface ipv6 show route

2.2 TCP/IP four-layer model, protocol suite

Link layer: device driver, interface card

Network layer: IP ICMP (Internet control message protocol) IGMP (internet group management protocol)

Transport layer: TCP UDP

Application layer: Telnet FTP POP3 SMTP

Mainstream server port: web:80 ftp:21,ssh:22,mysql:3306

Package: FTP- > TCP- > IP- > driver.

Distribute:. Driver-> IP- > TCP- > FTP

In an application, TCP is used in conjunction with UDP.

Encapsulated format: Ethernet header + IP header + TCP header + application header + data

Server type:

Repetitive: single threaded, slow but orderly

Parallel hairstyle: multithreading, thread pool / resource pool, fast but disordered with interlock risk

Port:

1-1023 unavailable ports, 1024-65535 available ports

Common ports:

Http:80/8080/8081/8090/3128/tcp

Https:443/tcp,443/udp

FTP:21/tcp

Telnet:23

Pop3:110/tcp

Tomcat:8080

Win2003:3389

Oracle:1521

Mysql:3306

Server:1433/tcp,1433/udp of SQL server database

Monitor:1434/tcp,1434/udp of SQL server database

Qq:1080

The difference between http protocol and https protocol: https protocol has more encryption processing, and there is no difference in user experience.

Example: check the port usage of native qq

1. View the pid of qq in the Task Manager

two。 Enter netstat-ano in cmd | findstr [pid of qq] can see the current port usage of QQ.

Attachment: http://down.51cto.com/data/2366416

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