Internet history
1969, Advanced Research Projects Agency, US Department of Defense.
ARPA (Advanced Research Projects Agency) developed the interconnection of computers in different places and formed ARPANET, the predecessor of the Internet.
In 1977- 1979, ARPAnet introduces the current TCP/IP architecture and protocol.
1986, the National Science Foundation (NSF) interconnected six supercomputing centers serving scientific research and education in the United States with TCP/IP protocol, supported local networks, formed NSFnet, and replaced ARPAnet as the backbone network of the Internet.
1989 changed its name to the internet and opened it to the outside world.
1994 the internet in the United States is completely taken over by commercial organizations.
Internet history in China
The first stage (1989-1early 994)-indirect Internet connection with email as the main application.
In the second stage (1992- 1994.4), the Internet is directly connected.
In the third stage (1994.4- now)-1994.4, China joined the Internet for the first time, and the construction of the Internet was fully rolled out.
See: Review of Internet Development in China.
c . AC . cn/GB/news/news _ special/5 _ years/ztyj/PPT/ybp 1/tsld 00 1 . htm
Www.cnnic.net.cn of China Internet Information Center is responsible for the application and registration of domestic IP addresses and domain names.
1996 has formed four major internet networks in China.
CERNET China Education and Research Network
The website of China Education and Research Computer Network is: www.edu.cn.
CSTNET
The website of Science and Technology Network is www.cnc.ac.cn, www.cstnet.net.cn.
ChinaGBN China Jinqiao Net National Public Economic Information Communication Network
The website of China Jinqiao Information Network is www.gb.com.cn.
ChinaNet China Public Internet provides computer international networking services for the public.
The website of China Telecom is www.chinatelecom.com.cn.
Other internet units
In addition:
China Unicom internet (UNINET)www.chinaunicom.com.cn
China netcom public internet (cncnet)www.cnc.net.cn
Www.chinamobile.com，cmnet (CMNET)
Www.ciet.net China International Economic and Trade Network
China Great Wall Internet (www.cgw.net.cn)
China Satellite Group Internet (CSNET)www.chinasat.com.cn
International export bandwidth
The total bandwidth of China's international exports is: 18599M m, and the connecting countries are the United States, Canada, Australia, Britain, Germany, France, Japan and South Korea. The distribution is as follows (July 2003)
Science and Technology Network (CSTNET):55M.
China net: 10959m
CERNET): 324m
China Unicom Internet: 1435m
China Netcom Public Internet (CNC CNET):2 1 12m.
Broadband China CHINA 169 Network (Netcom Group): 3465M.
China International Economic and Trade Network (CIETNET): 2m.
Cmnet (CMNET): 247m。
China Great Wall Internet (CGWNET): (under construction)
China Satellite Group Internet (CSNET): (under construction)
On June 5438+1October 65438+May, 2004, China Internet Network Information Center released the 13th statistical report on the development of China's Internet, which showed that nic.cn/html/Dir/2004/0115/2080.htm had made new progress.
By June 5438+February 3, 20031,the total capacity of China's international export bandwidth was 272 16M.
Internet definition
Internet is a worldwide computer system composed of computer networks of various types and scales that operate and manage independently. Chinese name is Internet, Internet, Internet. Everyone can enjoy and use all kinds of information on the Internet through the network connection.
Internet network based on TCP/IP protocol
Internet service provider
Internet content provider
The basic working principle of the internet
packet switching technology
Each computer can only transmit a certain amount of data at a time to ensure that all computers use resources equally.
Internet protocol IP
transmission control protocol (TCP)
Client and server (C/S structure)
The client sends a database or information query request, and the server program in the host computer accepts the request and replies in a specific format, which is then recognized by the client program and displayed to the user.
Client/server is based on LAN.
Browser and server (B/S structure)
Through the mature WWW browser technology, combined with browser scripting languages (VBScript, JavaScript…) and ActiveX technology, the user interface has fully realized the powerful functions that originally required complex special software, and saved the development cost.
The browser/server is based on WAN.
Internet changes the world.
Information acquisition and release
Internet communication
E-commerce/e-commerce
Internet telephone and fax
Network office
Distance education, telemedicine, online games, etc.
Internet users: 5965438+ million (male: 59.3% female: 40.7%)
Statistics on the number of netizens in China
Basic functions of the Internet
There are three basic functions: e-mail, remote login and file transfer.
E-mail: It is the most widely used, important and basic application on the Internet. It can transmit text, images, sounds and other media information, and send information to multiple recipients at the same time and forward it to the third party. It's slower than real-time fax, but cheaper.
Remote login: Users use the telnet command to temporarily make their computer the terminal of a remote computer, directly call the resources open to the outside world on the remote computer, query the database, retrieve materials, or use the remote computer to complete tasks that only a supercomputer can complete. Many services on the Internet are realized through telnet access.
File transfer: FTP (File Transfer Protocol) users can transfer files between two networked computers and get rich resources on the Internet for free.
In addition to the above basic services, it also has:
Newsgroup news: an open discussion of online topics.
Electronic bulletin board BBS: release information or make comments.
Chat MSN, ICQ: send messages, make calls, send files, and voice online.
Inquiry service (finger)
World Wide Web (WWW)
IP address; network address
IP (Internet Protocol) address, that is, the address expressed in Internet Protocol language.
A 32-bit binary number, divided into four segments, each segment is separated by dots, and each segment has 8 bits, which can be expressed as a decimal number less than 256.
An IP address consists of two parts: one is the network address and the other is the host address.
In order to meet the requirements of different network scales, IP addresses are mainly divided into three categories: A, B and C except for D (multicast address) and E (experimental address).
For example, the website of our school is 2 10.35.74.2.
IP address; network address
IP address space
Number of network addresses in the first byte Number of network hosts Total number of hosts
Class a network 0-127128 2 (8-1)1677 7214 224-22147483392.
Class b network128-19163842 (16-2) 65534216-21073709056.
C network192-223 2097152 2 (24-3) 254 28-2 532676608
Total 211366416843002 3753869056
Class A: 0.0.0.0~ 127.255.255.255/is the network address, and it is a large network.
Class B: 1 28.0.0 ~191.255.255/,and the second segment is a medium-sized network.
Class C: 192.0.0 ~ 223.255.255.255 The first 1, second and third paragraphs are network addresses and small networks.
Class d broadcast address reserved for multicast in class 224 ~ 239 D.
Class e 240 ~ 254 E are experimental addresses.
127.x.y.z in Class A address is reserved for loop testing.
None of 1 in each byte (8 bits) is allocated (that is, it cannot be 255), and all zeros in the first byte represent the local network address.
Those IP addresses belong to internal websites.
The IP addresses in the following ranges belong to local area network (intranet) addresses:
10.0.0.0 - 10.255.255.255
172. 16.0.0 - 172.3 1.255.255
169.254.0.0 - 169.254.255.255
192. 168.0.0 - 192. 168.255.255
Computers in the local area network can access computers on the Internet, but computers on the Internet cannot directly access computers in the local area network.
Dynamic and static IP addresses
DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses in the network.
Dynamic IP address: multiple users share multiple IP addresses. Every time a user dials into the network, the ISP will dynamically assign an IP address through DHCP.
The assigned ip address often changes (today's ip address is different from yesterday's, and this time the Internet is different from two hours ago), so it is a dynamic ip address.
Static ip address: it is a private IP address set by ISP for some users. The assigned IP address is always the same (Internet IP address is the same every day), so it is a fixed static IP address.
note:
Although the ip address of the computer in the local area network remains unchanged, it is different from the external computer. They can't get static IP addresses by applying to telecom service organizations such as CNNIC and ISP.
Preparations for establishing a website
Build a home or office.
Telephone lines, ISDN, ADSL, CABLE MODEN and home users who use dynamic ip to access the Internet can register dynamic domain names through software such as PeanutHull2.0, DNS2GO and Mountain Mountain.
Access to the Internet is the same as on the Internet, but users (internal websites) who access the Internet through local area network and campus network can access and register dynamic domain names through Web Mountain.
Please refer to the download URL
. com/soft/6352.html
2 10.35.74.2
The domain name of WWW server in the campus network center of Foreign Trade College.
Find the domain name and address of Shanghai Jiaotong University, Fudan University and 263 website.
Find the IP address corresponding to the domain name (using the ping command)
Domain name structure
Top-level Domain-Organization Domain
The type of organization or institution represented by the domain name.
Com business organization
Edu educational institutions or facilities
Gov non-military government agencies
international organizations
Mil military institutions or facilities
Network organization or institution
Org nonprofit organization
Top-level domain name-geographical domain
A domain name represents a country or region.
People's Republic of China (PRC)
Hong Kong, China
Mo China Macau
Tw, Taiwan Province Province, China
Sg Singapore
Great Britain
France
Jp Japan
China Secondary Domain Name System-Category Domain
The second-level domain name indicates the category.
Ac scientific research institute and science and technology management department
Industrial and commercial financial enterprises.
Edu Education Unit
Gov national government departments
Net internet, access to network information and operation center.
Org social organizations and non-profit organizations.
China Secondary Domain Name System-Administrative Region
Second-level domain name administrative region
Beijing
Shanghai
Tianjin Tj
Chongqing Chongqing
Jiangsu Js
Zhejiang Zj
Guangdong Guangdong
southern part of Shaanxi
Examples of domain names
Please analyze the industry and country (region) to which the following domain names belong:
World wide web /WWW
Information network based on Internet hypertext.
In a large library of the Internet, a Web node is like a book in the library, and a web page is a page in the book.
The home page is the starting point of a Web node, just like the cover or table of contents of a book.
URL (Uniform Resource Locator)
Uniform resource locator: the unique address of each web page.
/chn/yxsz/index.htm
, and then enter the "educational resources" webpage. ...
Collect the websites of the Ministry of Education, Sina and CCTV in "News"
After the above three operations are completed, use snagit to capture favorites (as in Example 2) and save them as screenshots of c:\test\ favorites. jpg。
Class assignment 2
Search operation
How many floors was the Big Wild Goose Pagoda in Xi when it was first built?
A. Seven floors B. Three floors C. Five floors D. Six floors
The earliest census figures in China are about:
A.436 million B.13.55 million C.5958 million D.4000 million.
Li Lin saw an indicator (WBC) on the high side in the blood routine test report. What does WBC mean?
A. Platelet count B. White blood cell count C. Red blood cell count D. Hemoglobin
There is a missed phone number on the mobile phone: 5879639 1. Before returning the call, I'd like to search which part of Shanghai the call is from.
A. Changning District B. Huangpu District C. Luwan District D. Pudong New Area
What is the original meaning of "Bao Gong" in the famous dish "kung pao chicken"?
A. dish name B. menu name C. place name D. official name E. person's name
Save the search results to c:\test\ search exercise. Txt, where only the question number and the selected answer are required.
Work packaging
Check whether there are:
Htm web page files and corresponding subfolders
Two jpg image files
Two text files
Take your extension number (two digits)+name +IE to work. Rar is used as the file name, and the above contents are compressed (packaged) and sent as attachments.
Here's how to send an email.
two
E-mail account settings before OE was enabled.
Your e-mail address
0 10 100 1@shift.edu.cn
Account name (user name): Your student number.
Password: the last five digits of the ID number (the last digit may be X or X).
Capacity: 2M
Tools → Account → Mail → Add → Mail →
(If there are other students' accounts, please delete them first. )
Display name (sender's name) → Fill in name.
E-mail (reply address) → Fill in your real e-mail.
POP3 Receiving Server: The address of our receiving server is mail.shift.edu.cn.
SMTP mail server: The address of our school mail server is mail.shift.edu.cn.
Account Name → Fill in your account name.
Password → Fill in your password.
Remember the password → Select tick.
Tools → Accounts → Mail → Select Current Account → Properties → Server →
Check the box before "My server needs authentication"
classwork
File → New → Mail → (or create mail)
Recipient →
Teacher email user name @shift.edu.cn
Subject → extension number (two digits)+name +IE homework
Email body → Write a sentence casually, or suggest this course.
Finally, attach your student number, name and class.
E-mail can have a background (such as creating sunny in the drop-down menu of e-mail). ).
Split line (insert → horizontal line)
Attachment → Select your packaging job file in the c:\test folder.
Such as: 0 1 three IE assignments. rar
Click Send.
Check whether there are messages in the Outbox folder. If there is a message, it is not sent.
Check whether there is any mail in the Sent Items folder. If there is, the mail has been sent.
Write an example of email.
Apply for free e-mail address
Apply for free email in citiz or Sohu.
Website to apply for citiz free email:
mail.citiz.net
Or/index.jsp.
Pay attention to the receiving server (POP3) and sending server (SMTP) mentioned in the FAQ.
Sending and receiving server
Sending server
SMTP outgoing mail server (outgoing mail office)
Simple mail transfer protocol
The sending server of our school Songjiang: mail.shift.edu.cn.
Receiving server
POP3 receiving server (receiving post office)
Post office protocol 3
The receiving server of Songjiang in our school: mail.shift.edu.cn.
Where you have an account, you can get letters from the receiving server there.
Comparison table of common smtp and pop3 servers
OE basic settings
The sending/receiving server can be on the same machine or on different machines (including off-site).
To, cc, bcc
Multiple people: Separate email addresses with semicolons or commas.
Address book and its application (import/export)
Add attachment
Send text, pictures, sounds and other documents as attachments.
Handling of receiving e-mail attachments
Open (watch out for viruses)
protect
Tools → Options → Security → The meaning of "Do not save or open attachments that may contain viruses"
View e-mail properties
OE advanced settings
Multi-account setting
Keep mail backup
Tools → Accounts → Mail → Select Current Account → Properties → Advanced →
Keep a copy of the message on the server.
certificate
Tools → Account → Mail → Select Account → Properties → Server →
My server needs authentication.
OE mail rules
Messages → Create rules from messages to block senders.
Tools → Mail Rules → Mail →
Rule condition, rule operation, rule description and rule name.
function
Stop spam
Classified storage (create folders first)
OE other operations
FOLDER
Combine the mail rules to distribute the received mail to different folders.
Tools → Add Sender to Address Book
Save e-mail
Menu: File → Save As
Clipboard (save part of the message body)
Print e-mail
View → sorting method, column and layout
Mail security
Using digital certificate, PKI, symmetric encryption algorithm, digital signature, digital envelope and other encryption technologies, a highly secure encryption and decryption and identity authentication system can be established to ensure that electronic transactions are carried out effectively and safely, so that information will not be known by other parties except the sender and the receiver (confidentiality); Ensure that it is not tampered with during transmission (integrity and consistency); The sender is convinced that the receiver is not forged (authenticity and unforgeability of identity); The sender cannot deny his sending behavior (undeniable).
CA (Certificate Authority), as an authoritative, reliable and impartial third-party organization, is responsible for issuing and managing digital certificates required by all entities participating in online transactions. As an authoritative organization, it effectively manages keys, issues certificates to prove the validity of keys, and associates public keys with an entity (consumer, merchant, bank).
Mainly used for: online tax filing, office work, bidding, trading, mail and business administration.
Digital certificate: the identity card of an individual or unit on the Internet. A strict identity authentication system is established by using symmetric and asymmetric cryptography.
Digital signature means that the sender generates a digest from the message and encrypts the digest with his own signature private key. The message and the digital digest encrypted with its own signature private key are combined into a digital signature.
E-key: also known as electronic key, is actually a special hardware storage medium with a unified encryption algorithm, which can decrypt specified encrypted data and store digital certificates.
Email truck
Mail truck is a tool to access HTTP and FTP through mail gateway server. Usually, if it's a web page that takes you a few minutes to connect, or a file that can only be downloaded at a speed of 0.2k/ s, or an address that you can't directly access (such as 169 A/B users often encounter), the email truck can help you complete all this by email. All you have to do is fill in the URL, or just "copy to clipboard". The basic technology of mail truck is exactly the same as that of Mr. Cool, but the design goal is to completely surpass Mr. Cool. There are no common bugs in Mr Cool, and the monitoring dialog box pops up at the top, and there will be no infinite loop if the sending queue fails. Added batch processing, source file downloading and more powerful monitoring settings. And the interface is absolutely refreshing.
Mail express
Sometimes you may encounter this situation: you need to send an email to your friend immediately and quickly, but ordinary email sending methods can't guarantee that the email will be sent to the other party's mailbox immediately.
Foxmail provides the function of express delivery, which is characterized by finding the server where the recipient's mailbox is located and sending the mail directly to the other party's mailbox. In this way, when you send it, your friends can receive it immediately.
To use the mail express function, just click the "Mail" menu or "Express" in the toolbar after writing the mail.
Note: EMS can only be sent to one recipient, and only one email address can be filled in at the recipient's office.
In addition, the function of express mail needs to call the domain name server (DNS) to query the IP address corresponding to the recipient's mailbox, so the domain name server address must be filled in the system. If you fill in the domain name server address in the ICP/IP properties dialog box of Windows system, Foxmail will automatically obtain and use the address. Users can also select "Mail Express" in the pop-up dialog box through "Options | System Settings" in the Foxmail menu and fill in the IP address of the domain name server. You can fill in two domain name server addresses, or you can just fill in the first one.
Foxmail express
Need to call the domain name server (DNS) to query the IP address corresponding to the recipient's post office.
If the domain name server address is filled in the TCP/IP attribute of Windows system, Foxmail will automatically use this address.
Set the Foxmail menu: Options → System Settings → Mail Express, and fill in the IP address of the domain name server.
IP address of DNS server of Trade College: 2 10.35.72. 1.
IP address of Shanghai telecom DNS server:
202.96. 199. 133 202.96.0. 133
Find local DNS server
If you don't know the IP address of the local DNS server, you can get it by the following methods:
For Windows2000/XP system, click Windows Start | Programs | Accessories | Command Prompt to open the command prompt window and execute the command ipconfig /all. The listed information will include the IP address information of the DNS server.
For Windows98 system, you can execute the command of "winipcfg" through "Run" in the Windows start menu, and view it from the column of "DNS server" in the details of the pop-up dialog box.
Email application
Newsgroup
news.webking.com.cn
news.sta.net.cn
news.zj.cninfo.net
Subscribe to free e-magazine (mailing list)
www.tom.com/maillist
mlist. 163.com
Mail greeting card
cards. 163.com
practice
Save the teacher's email address and your other addresses in the address book.
Send letters using OE
Recipient:
slx@shift.edu.cn
Category III and IV: SLX 1@shift.edu.cn
Cc: yourself and your other email addresses.
Secret delivery:
pc@shift.edu.cn
Category III and IV: PC 1@shift.edu.cn
Topic: Zhang San 05 Exercise 2
practice
Sending letters using OE (continued)
Please note that the text must be in plain text format.
According to the serial number of the computer used, how many times will Legend of the Condor Heroes correspond?
(between 4 1-80, minus 40, minus more than 80 minus 80) and the first 200 words are used as the email body, and the professional and Chinese names are signed at the end.
Attached is the picture in the lower right corner of the home page of Foreign Trade College.
Check it, you can send it!
practice
Create folder teachers in OE.
Establish email rules to automatically put teachers' emails into teachers' folders.
Save the message as a file
Comparison between OE and other email sending and receiving software
Advantages of Foxmail
Remote mailbox management
Access password function
Mail express forwarding function
eight
About network firewall
Disconnect (restore) the network
system setup
Custom security level
detailed information
Procedural rules
Security log
computer network
Refers to the collection of autonomous computer interconnection systems connected based on network protocols for the purpose of sharing resources and communicating with each other.
Function: Enjoy resources * * *
Communication methods (e-mail, collaborative work)
Network classification
Local area network
A small area, an office or a building.
Wide area network (WAN)
Covering dozens or hundreds of kilometers or even the whole earth.
Metropolitan area network)
A computer network covering a city.
network topology
Computer physical connection mode
Bus type
The information sent by the computer is received by the computer on the Internet.
There is only one actual reception (destination address)
Advantages: simple, easy to use and master, using less cables.
Disadvantages: low efficiency and difficult maintenance.
Network topology: bus
network topology
star
Hub hub forwarding
Advantages: easy expansion, strong reliability and convenient maintenance.
Disadvantages: Hub failure, network paralysis.
Use more cables.
Network topology: star
network topology
Ringed
Token transmission
Get a token to send information.
Advantages: every computer can access the token, and no computer can monopolize the network and enjoy the network resources fairly.
Disadvantages: poor reliability, difficult fault diagnosis, and computer interference with network operation.
Network topology: ring
network adapter
Network adapter → network card, MAC address
Insert the computer motherboard slot.
Motherboard integration
Connection network type Ethernet, ring network
Transmission medium (network cable) type BNC RJ45
The bus types used by the computer are ISA and PCI.
Modem/modem module
telephone wire
lady
ISDN mode
modulator/demodulator
Cable TV line
Cable module
Power cord
Electric module,
Community private line FTTB+ LAN
wireless
Wireless modem
Transmission medium (1)
Transmission media → wired media and wireless media.
Wired media
Unshielded Twisted Pair
UTP, Unshielded Twisted Pair (UTP).
Several pairs of twisted wires are encapsulated in a plastic sleeve.
Class III line: transmission rate 10Mbps.
Category 5 line: transmission rate 100Mbps.
Connection distance:/kloc-within 0/00 meter.
STP
There is a layer of shielding outside, 500Mbps, and the cost is high.
The transmission medium (2)
coaxial line
A shielding layer consisting of a central copper wire, an outer insulating layer and an outer metal mesh, and an outermost sleeve.
10Mbps, hundreds of meters, cheap
light guide
100Mbps to 2Gbps
Thousands of meters, good confidentiality.
Wireless media
Radio system, ground microwave system, satellite microwave system, infrared transmission system.
Unshielded Twisted Pair
light guide
network connections
Network connection device:
Central (central)
Due to the attenuation and noise of signals in network transmission media, useful data signals become weaker and weaker. Therefore, in order to ensure the integrity of useful data and transmit it in a certain range, the received weak signal should be separated, regenerated and amplified by the transponder to keep it consistent with the original data.
Repeater (repeater)
Hub can be said to be a special repeater. As the central node between network transmission media, it overcomes the defect of single media channel. The advantage of hub-centric is that when a line or a node in the network system fails, it will not affect the normal work of other nodes on the network. Hubs can be divided into passive hubs, active hubs and intelligent hubs.
A switch
Network switching technology: structured network solution. It is a new network application form when the computer network develops to the high-speed transmission stage. So that the existing network technology can improve the performance by switching devices.
network connections
Internet interconnection equipment:
a bridge
A bridge is a bridge that establishes a connection between one LAN and another LAN.