1. 1 InterNet InterNet 52807 E-mail : claven@cc.nctu.edu.tw consult@cc.nctu.edu.tw 52807 E-mail : claven@cc.nctu.edu.tw consult@cc.nctu.edu.tw

2. 2 *Introduction To Internet *Domain Name & Internet Address *The Basic Services of Internet *Your First Steps on Internet *Advanced Services of Internet *Introduction To Internet *Domain Name & Internet Address *The Basic Services of Internet *Your First Steps on Internet *Advanced Services of Internet

3. 3 Introduction to Internet hWhat is a network? hWhat is Internet hA Brief History of Internet hWhat is a network? hWhat is Internet hA Brief History of Internet

4. 4 What is a network? *Networks : computers are connected in such a way they can communicate. *Local-area Network (LAN): the network is composed of computers in the same area. *Wide-area Network (WAN): the network con- sists of computers spread across a larger area *Networks : computers are connected in such a way they can communicate. *Local-area Network (LAN): the network is composed of computers in the same area. *Wide-area Network (WAN): the network con- sists of computers spread across a larger area

5. 5 LAN Accounting Shipping AdministrationR&D Production N etwork Connection

6. 6 WAN Seattle San Francisco Dallas Omaha Toronto

7. 7 Why Networks? *Communication E-mail *Common Data cPolicy cBBS *Shared Resources cPrinters cHard Disks

8. 8 What is The Internet? *A network of networks *A large collection of independent networks, all of which run TCP/IP, that are tied together.

9. 9 The Internet NSFNET Other NETS APARNET MILNET TANET

10. 10 What can Internet Do for Users? *Communication cElectronic Mail cI-Phone *Learning and Discussing tool cBBS cUsenet Collecting information cLibrary Searching *Entertainment cMUD *Commercial cOn-Line Order

11. 11 Domain Name & IP Address

12. 12 IP Address uniquely *A way to identify uniquely an area of the Net or an computer on the Net *Consists of 4 digits, each of which ranges from 0 to 255 (usually 1-254), separated by dot(.) *140.113.1.1 c140 : Taiwan c113 : NCTU ask your network manager for an IP address *If you want to connect your computer to Inter-net, ask your network manager for an IP address

13. 13 Domain Name System (DNS) Internet TW EDU NCTUCC CCSUN1 140.113.4.11 --> ccsun1.cc.nctu.edu.tw

14. 14 Domain Name System(DNS) *A symbolic name for an IP-address (machine) *A domain: an organization level within Internet *Domains can be connected together (by dot (.)) to create a unique identifier. *left to right: most specific to most general *Top-level : organizational or geographic *ask your network manager for your domain Name(FQDN, Full Qualified Domain Name)

15. 15 Top Organization Domains

16. 16 Top Geographic Domains

17. 17 TANet Domain twedu.tw org.tw nctu.edu.tw nthu.edu.tw ntu.edu.tw cc.nctu.edu.tw cis.nctu.edu.tw csie.nctu.edu.tw..... com.tw gov.tw net.tw

18. 18 Hostname VS Domainname TW EDU NCTUCC CCSUN1 140.113.4.11 --> ccsun1.cc.nctu.edu.tw 1ccsun1 is the hostname of 140.113.4.1 1ccsun1.cc.nctu.edu.tw is the domainname(FQDN) of 140.113.4.1 1When you connect to a machine within the same domain, you can just use that machine's hostname

19. 19 T he Basic Service of Internet `Virtual Terminal Service (telnet) `File Transfer Service (ftp) `E-Mail Service (SMTP)

20. 20 Virtual Terminal Service (telnet) $telnet host Trying...Connected to host Escape Character is '^]' host's O.S. Version(host) login: <--- UserName passwd: <--- Password $........................................................ $logout Connection closed by foreign host................................................ W ork as if you are on host Use Resources and Services of host Come back to Local

21. 21 File Transfer Service (ftp) $ftp host Connected to host. 220 host FTP server ready Name(host:username): Password: User username logged in. ftp> ftp> quit (Come back to the local) O K. Connect to FTP Server. You can get or put files now. E nter your username/ password

22. 22 F ile Transfer Service (ftp) (Cont.) *Use get command to copy file(s) from the remote host. ftp> get *Use put command to copy local file(s) to the remote host. ftp> put *You can use cd, ls,....,etc. as in UNIX *Use ? in the 'ftp>' prompt to get help *You should be a user of the remote host to get /put files

23. 23 Anonymous FTP *Some hosts on Internet are set up in a way that you can use file transfer service to get public domain utilities without an account on it. anonymous/ftp claven@cc.nctu.edu.tw (E-mail) $ftp host Connected to host. 220 host FTP server ready Name(host:username): anonymous/ftp Password:claven@cc.nctu.edu.tw (E-mail) ftp> Do as normal ftp

24. 24 FTP Exercise ftp nctuccca.nctu.edu.tw ftp claven@cc.nctu.edu.tw pwd binary cd /NCTU/SLIP-Service ls get slippr13.zip quit * Anonymous FTP between PC and a server d:\> ftp nctuccca.nctu.edu.tw login: ftp password: claven@cc.nctu.edu.tw ftp> pwd ftp> binary ftp> cd /NCTU/SLIP-Service ftp> ls ftp> get slippr13.zip ftp> quit

25. 25 FTP Exercise (Cont.) ftp ccsunxx YOUR USERNAME * Transfer files by your account d:\> ftp ccsunxx login: YOUR USERNAME YOUR PASSWORD lcd d:\ ? lcd ascii ? ascii get.cshrc cshrc.nod quit *password: YOUR PASSWORD ftp> lcd d:\ ftp>? lcd ftp> ascii ftp>? ascii ftp> get.cshrc cshrc.nod ftp> quit

26. 26 E lectronic Mail (SMTP) *You can use Mail (BSD), mailx(SV), or elm to send your electronic letter to a remote user. *Mail user@host < letter.txt cYou send a file named letter.txt created in advance. chost should be a domain name unless you and the user are within the same domain. *Mail user@host cEnter your Subject and your message, and press CTRL-D to complete the input of your message.

27. 27 Your First Steps on Internet %How to display the status of machines %How to check if a host is currently Available %How to list the users logged on to a system %How to talk to other users

28. 28 Using the rup command *The function of the rup command: cDisplay the status of the machines within the same subnet *rup

29. 29 Using the ping Command *The function of the ping command cTell you if a remote computer is currently available on the network. *ping : Display a short message *ping -s : Also show the performance of the link between you and the remote host cUse Ctrl-C to end the ping -s command.

30. 30 Using the rusers/ku Command *Use rusers/ku to display the users logged into the systems within the same subnet. *rusers

31. 31 Using the talk command *The function of the talk command: cLet you make a on-line conversation with other users *talk @ cUse Ctrl-C to terminate conversation. *Using the mesg cmesg y : allow the talk request cmesg n : reject the talk request cmesg : display the current mesg setup *Other version of talk: cctalk : Can use Chinese cytalk : Can talk with users on the systems not using UNIX ccytalk: Can use Chinese

32. 32 E xample of talk Message from Talk_Daemon@ccsun2 at 16:00 talk: connection requested by jami@ccsun2 talk: respond with: talk jami@ccsun2 T he message shown on my screen Jami on ccsun2 want to talk with freddy Step1: Use rusers to find if freddy is logged onto some sysytem. Step2: Ah, freddy is on ccsun1 Step3: talk freddy@ccsun1 )freddy can issue talk jami@ccsun2 to begin the on-line conversation with jami

33. 33 A dvanced Services of Internet `Usenet News `Gopher `BBS `WWW

34. 34 U senet News *A collection of discussion groups that serves as a giant bulletin board. cYou can obtain the information you want from News. cYou can post a questions to the News and get your answer. cYou can respond your opinion on some topic or answer the question asked by others. *Use the tin command to read Usenet News Please use your eyes more than your fingers *As a novice user, Please use your eyes more than your fingers.

35. 35 Gopher *Gopher is an information retrieval system that let you search information from all around the world. *Use the gopher command to enter the gopher system

36. 36 BBS (Bulletin Board System) *Integrate a few of network services as a whole system. cPost and read of bulletin board (similar to news) cElectronic Mail cTalk cRetrieve files c.... *Use telnet and follow the direction to enter BBS

37. 37 WWW (World-Wide Web) *WWW is a multi-media, hyper-text information providing system. *On PC Windows 95/NT cUse netscape or mosaic to browse WWW *On Workstation X-windows Screen cUse netscape or mosaic to browse WWW