url, ftp & powertools csc1720 – introduction to internet essential materials

URL, FTP & PowerToolsURL, FTP & PowerTools

CSC1720 – Introduction to CSC1720 – Introduction to InternetInternet

Essential MaterialsEssential Materials


All copyrights reserved by C.C. Cheung All copyrights reserved by C.C. Cheung 2003.2003.

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OutlineOutline

Universal Resource Locator (URL)Universal Resource Locator (URL) Remote Access/Login - TelnetRemote Access/Login - Telnet File Transfer Protocol (FTP)File Transfer Protocol (FTP)

– Client and Server softwareClient and Server software PowerToolsPowerTools

– Discuss different types of Internet Discuss different types of Internet toolstools

SummarySummary



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Universal Resource Universal Resource Locators (URL)Locators (URL) It is also called “Uniform Resource It is also called “Uniform Resource

Locators” which is used to identify Locators” which is used to identify resources on the Internet.resources on the Internet.

It has the following general format:It has the following general format:– SchemeScheme::object-addressobject-address– SchemesSchemes can be can be

http, ftp, gopher, telnet, file, mailto, newshttp, ftp, gopher, telnet, file, mailto, news

– Object-addressObject-address //fully-qualified-domain-name/document-path//fully-qualified-domain-name/document-path

– E.g. http://www.cse.cuhk.edu.hk/index.htmlE.g. http://www.cse.cuhk.edu.hk/index.html



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Universal Resource Universal Resource Locator (URL)Locator (URL) URL is a scheme for specifying URL is a scheme for specifying Internet Internet

resourcesresources (WEB page, email address, (WEB page, email address, gopher site, newsgroups, various files, ...) gopher site, newsgroups, various files, ...) using a single line of using a single line of printable charactersprintable characters. .

This scheme encompasses all major This scheme encompasses all major Internet protocols, including FTP, Gopher, Internet protocols, including FTP, Gopher, News, HTTP, ... News, HTTP, ...

It is the foundation tool for WEB pages to It is the foundation tool for WEB pages to specify specify hyperlinkhyperlink. .



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URLURL

http://http:// www.cse.cuhk.edu.hkwww.cse.cuhk.edu.hk:8080:8080/~csc1720/lecture.notes/url/index.html/~csc1720/lecture.notes/url/index.html

Protocol Protocol - Specifies the protocol used in accessing the resource. - Specifies the protocol used in accessing the resource. Domain NameDomain Name - Domain name of the server on which the - Domain name of the server on which the

resource is located resource is located – (Numerical) IP Address can be used instead. (Numerical) IP Address can be used instead.

Port Port - The port number to be used to access the resource.- The port number to be used to access the resource.– If omitted, the If omitted, the default valuedefault value for the specified protocol will be used. for the specified protocol will be used.

Directory and Resource DetailsDirectory and Resource Details - Path- Path information required to information required to locate the resource on the server. locate the resource on the server. – This field may vary considerably. This field may vary considerably.



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Network PortsNetwork Ports



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URL Example: HTTPURL Example: HTTP

http://leonardo.utirc.utoronto.ca:8080/cgi-bin/http://leonardo.utirc.utoronto.ca:8080/cgi-bin/ Designed for distribution of hypertext documents. Designed for distribution of hypertext documents. HTTP is a client-server protocol. HTTP is a client-server protocol. Two important features: Two important features:

– The ability to return to the client (e.g. Netscape) not just The ability to return to the client (e.g. Netscape) not just files (e.g. html files), but also information generated by files (e.g. html files), but also information generated by programs running on the server (e.g. database searching programs running on the server (e.g. database searching results). results).

– The ability to take data sent from the client and pass this The ability to take data sent from the client and pass this information on to other programs (called CGI programs) information on to other programs (called CGI programs) on the server for further processing (e.g. order on the server for further processing (e.g. order processing). HTTP URL in this case carries the processing). HTTP URL in this case carries the information from the client to the server.information from the client to the server.



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URL Example: mailtoURL Example: mailto

Use mailto as the protocol. Use mailto as the protocol. Followed by the email address of the Followed by the email address of the

target recipient. target recipient. Note the omission of "//", between Note the omission of "//", between

mailto: and the email address. mailto: and the email address. A email interface (e.g. Netscape Mail) A email interface (e.g. Netscape Mail)

will be created to allow you to will be created to allow you to compose and send your email. compose and send your email.

mailto:[email protected]:[email protected]



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URL Example: newsURL Example: news

Use news as the protocol. Use news as the protocol. Followed by the desired newsgroup. Followed by the desired newsgroup. Note the omission of "//", between news: Note the omission of "//", between news:

and the newsgroup. and the newsgroup. A news reader (e.g. Netscape News) will be A news reader (e.g. Netscape News) will be

created. created. News server etc. must be properly News server etc. must be properly

configured. configured. news:cuhk.cse.csc1720 news:cuhk.cse.csc1720



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URL Example: FTPURL Example: FTP

ftp://s123456:[email protected]/images/dragonball.gif ftp://s123456:[email protected]/images/dragonball.gif

username (s123456)username (s123456) & & password (abcdefg)password (abcdefg) Not secure. Not secure. Directory paths are relative to the user's home Directory paths are relative to the user's home

directory.directory.– In this case, /users/students/s123456/images/dragonball.gif. In this case, /users/students/s123456/images/dragonball.gif.



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TelnetTelnet

Internet allows you to use the Internet allows you to use the resources of a distant computer resources of a distant computer somewhere else in the world.somewhere else in the world.

Telnet is a client/server model.Telnet is a client/server model. The distant computer (host) allows The distant computer (host) allows

multiple users to access its resources multiple users to access its resources at the same time.at the same time.

Telnet clients are available in different Telnet clients are available in different Operating system: Linux, Unix, Operating system: Linux, Unix, Macintosh, Windows.Macintosh, Windows.



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TelnetTelnet

These program allows you to log on to These program allows you to log on to much powerful computers and perform much powerful computers and perform tasks like you are actually working on tasks like you are actually working on the remote machine.the remote machine.

Telnet usually needs Telnet usually needs username/password, but not always username/password, but not always (e.g. library.cuhk.edu.hk).(e.g. library.cuhk.edu.hk).

Some good telnet clientSome good telnet client– NetTermNetTerm – one of the best telnet client – one of the best telnet client– SimpTermSimpTerm – Another one. – Another one.– SSHSSH – using encrypted channel. – using encrypted channel.



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Telnet FigureTelnet Figure



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Remote Access Remote Access ExampleExample

Figure 28.2 Illustration of a remote desktop service. Software permits the display on a user’s computer to show the screen image from a remoter computer.



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How Remote Desktops How Remote Desktops OperateOperate

A remote desktop service A remote desktop service operates similar to a remote login operates similar to a remote login service.service.– Invokes an applicationInvokes an application– Specifies a remote computerSpecifies a remote computer– Takes over the screen, keyboard, Takes over the screen, keyboard,

and mouseand mouse– See:See:

http://www.uk.research.art.com/vnc/http://www.uk.research.art.com/vnc/



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Remote Desktop Remote Desktop ExampleExample



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File TransferFile Transfer

Using the Internet’s FTP (Using the Internet’s FTP (FFile ile TTransfer ransfer PProtocol) to upload/download files.rotocol) to upload/download files.

FTP works on client/server model.FTP works on client/server model. You should run FTP client software to You should run FTP client software to

connect to a FTP server on the Net.connect to a FTP server on the Net. You must use an account to login.You must use an account to login.

– Username / passwordUsername / password– Anonymous / email addressAnonymous / email address

HTTP can be used for downloading file HTTP can be used for downloading file on the Web, but not as efficient as FTP.on the Web, but not as efficient as FTP.



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Mode of TransferMode of Transfer

FTP has two ways of transferring data FTP has two ways of transferring data – ASCII and Binary ASCII and Binary

ASCII ModeASCII Mode – The client and server try to ensure that the characters they The client and server try to ensure that the characters they

transfer have the same meaning on the target computer transfer have the same meaning on the target computer as they did on the source computer. as they did on the source computer.

– The most notably example is the differences in The most notably example is the differences in line line delimiterdelimiter between Unix and PC. between Unix and PC.

– ASCII transfer is (usually) the default. ASCII transfer is (usually) the default. Binary ModeBinary Mode

– The bit sequence of the file is preserved during the The bit sequence of the file is preserved during the transfer. transfer.

– The original and the copy are bit-by-bit identical. The original and the copy are bit-by-bit identical.



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Mode of TransferMode of Transfer

FileFile ExtensionsExtensions ModeMode

Text fileText file .txt.txt ASCIIASCII

Spreadsheet, ExcelSpreadsheet, Excel .xls, .xlw.xls, .xlw BinaryBinary

Database fileDatabase file .dbf.dbf BinaryBinary

Word processing Word processing filefile

.doc.doc BinaryBinary

Program source Program source codecode

.c, .java.c, .java ASCIIASCII

E-mailsE-mails N/AN/A ASCIIASCII

Unix tar fileUnix tar file .tar.tar BinaryBinary

Compressed fileCompressed file .Z, .zip, .gz, .ar.Z, .zip, .gz, .ar BinaryBinary

ExecutableExecutable .exe.exe BinaryBinary

Multimedia fileMultimedia file .gif, .mov, .wav.gif, .mov, .wav BinaryBinary

HTML fileHTML file .html, .htm.html, .htm ASCIIASCII



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FTP ExampleFTP Example

Figure 27.2 The path data takes when a server sends a copy of a remote file in response to a user’s request. The FTP client and FTP server programs use TCP/IP to communicate.



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FTP clientFTP client

Reference

You can drag andDrop files fromLocal PC to remoteFTP site or vice versa.



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FTP ServerFTP Server



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FTP serverFTP server

Server is running

Server is not running



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PowerToolsPowerTools

CommunicationsCommunications– IRC, MessengersIRC, Messengers

ConnectivityConnectivity– Connection Monitoring, Download Connection Monitoring, Download

Managers, Web Accelerators, Time Managers, Web Accelerators, Time SynchronizersSynchronizers

E-mailE-mail– Anti-Spam, E-mails/News ReadersAnti-Spam, E-mails/News Readers

Internet ToolsInternet Tools– File Sharing, UtilitiesFile Sharing, Utilities



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PowerTools (cont’)PowerTools (cont’)

Network ToolsNetwork Tools– DNS lookup utilities, Trace-route, DNS lookup utilities, Trace-route,

Ping, SSH, TelnetPing, SSH, Telnet SecuritySecurity

– Cookie, Firewalls, Internet MonitoringCookie, Firewalls, Internet Monitoring ServersServers

– FTP, MiscellaneousFTP, Miscellaneous Web Browsers & ToolsWeb Browsers & Tools

– Ad Killers, Offline browserAd Killers, Offline browser



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Trillian – multi-chat Trillian – multi-chat clientclient SupportSupport for IRC, AIM, ICQ, MSN, Yahoo Messenger. for IRC, AIM, ICQ, MSN, Yahoo Messenger.



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Connection MonitoringConnection Monitoring

Report the full bandwidth of your connection as any given Report the full bandwidth of your connection as any given time, help you to explore the connection potential.time, help you to explore the connection potential.

Customize the daily, weekly, monthly traffic reports – Customize the daily, weekly, monthly traffic reports – DU MeterDU Meter..



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Performance TuningPerformance Tuning

Internet Internet Optimizer Optimizer programprogram

Promotes faster Promotes faster connection by connection by tweaking some tweaking some hidden windows hidden windows settings.settings.

Example:Example:– TweakMasterTweakMaster



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Connection Sharing - Connection Sharing - WingateWingate Save money for Home Internet Save money for Home Internet

Sharing – Sharing – WingateWingate..



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Download ManagersDownload Managers

Help you download files from the Internet, resume downloading.Help you download files from the Internet, resume downloading. Most famous – Most famous – GetRightGetRight, , Go!Go!ZillaZilla



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FlashGetFlashGet

Automatically split Automatically split files into sections files into sections and download and download simultaneously.simultaneously.

Multiple Multiple connections are connections are opened to each file, opened to each file, explore the most explore the most efficient way to efficient way to utilize the available utilize the available bandwidth.bandwidth.

Download time is Download time is drastically reduced.drastically reduced.

ReferenceReference

5 individual connections



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Web AcceleratorsWeb Accelerators

Increase the Web Increase the Web surfing speed by surfing speed by using cache using cache technology to technology to store the content store the content of the web page.of the web page.

Use the idle Use the idle bandwidth to bandwidth to prefetch the prefetch the URLs.URLs.

ReferenceReference



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Time SynchronizersTime Synchronizers DimensionDimension

ReferenceReference A time A time

synchronization synchronization tool for Windows tool for Windows platformplatform

Different Time server



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Email Reader / Email Reader / SPAM PunisherSPAM Punisher

ReferencReferencee

ReferencReferencee



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File SharingFile Sharing – – WinMX/NapsterWinMX/Napster A file-sharing program A file-sharing program - share and download any file type.- share and download any file type.



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UtilitiesUtilities - Gator - Gator eWalleteWallet Store your information in your computer.Store your information in your computer.

No need toFill all the InformationAgain andAgain

Demo



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UtilitiesUtilities - WebFerret - WebFerret

Query multiple search engines from your desktop - Query multiple search engines from your desktop - referencereference

QueryInternetCourse

DifferentSearchEngine



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Packet MonitoringPacket Monitoring

Understand theTCP/IP protocoland watch thepackets your systemExchanges withRemote system

Reference

DEMO



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Network Traffic Network Traffic MonitoringMonitoring

Packet Packet Reconstruction, Reconstruction, manipulation, manipulation, forging forging

- eEye Iris- eEye Iris



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DNS lookup utilitiesDNS lookup utilities

Reference

Allow you to lookupThe IP address for aGiven hostname orReverse lookup theHostname from a givenIP address



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Trace-routeTrace-route

Analyze the hop times, trace the routing path to the destination - Reference



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PingPing

Test if the remote system is running and Test if the remote system is running and accessible by your localhost - Referenceaccessible by your localhost - Reference



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CookieCookie

Browsers store information about what Browsers store information about what the user has done on the Internet, the the user has done on the Internet, the visited websites.visited websites.

Cookies are files that may contains Cookies are files that may contains some personal information about the some personal information about the user.user.

We need to clean up the history, cache We need to clean up the history, cache and cookie, in order to free more hard and cookie, in order to free more hard disk space and handle the privacy disk space and handle the privacy concerns.concerns.



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Cookie and its Cookie and its ManagerManager

ReferenceReference RemoveRemove

– CacheCache– CookiesCookies– HistoryHistory– Drop down Drop down

address baraddress bar– auto-auto-

complete complete formsforms



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FirewallsFirewalls

Manage your personal firewall - ReferenceManage your personal firewall - Reference



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FTP ServerFTP Server

Support multiple FTP servers & FTP Client/Server - Reference



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Ad FilterAd Filter

The most popular one is “The most popular one is “WebWasherWebWasher””

Identify and remove banner ads, Identify and remove banner ads, pop-up ads, animated graphics.pop-up ads, animated graphics.

Many companies install it in order to Many companies install it in order to keep employees less distracted.keep employees less distracted.

WebWasher can reduce bandwidth WebWasher can reduce bandwidth consumption by about 45%.consumption by about 45%.

Demo now!Demo now!



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Ad Filter ExampleAd Filter ExampleDeactivate filtering Activate filtering



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Popup Ad Filter FigurePopup Ad Filter Figure

DemoDemo



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Popup Killer / Popup Popup Killer / Popup StopperStopper

ReferencReferencee

StopperStopper



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Some Popular Ad FilterSome Popular Ad Filter

NameName TypeType URLURL

WebWashWebWasherer

FreewareFreeware http://www.webwasher.com/http://www.webwasher.com/

Internet Internet JunkbusterJunkbusterss

FreewareFreeware http://www.http://www.junkbustersjunkbusters.com.com//

AdSubtracAdSubtractt

FreewareFreeware http://www.http://www.adsubstractadsubstract.com.com//

WebFree WebFree (Mac)(Mac)

SharewarSharewaree

http://www.http://www.falkenfalken.net/.net/webfreewebfree//



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Offline browserOffline browser

ReferenceReference

Site mirroring Site mirroring tool for off-tool for off-line browsingline browsing



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WebCopier WebCopier – Offline – Offline browserbrowser

Mirrorour CUHKwebsite

Download 5 filessimultaneously

Download website and store them locally on the hard drive.Download website and store them locally on the hard drive.



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WebCopier – exampleWebCopier – example

Local files



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SummarySummary

URL is used to specify all Internet URL is used to specify all Internet resources.resources.

Telnet is a client program which connects Telnet is a client program which connects to remote powerful computer and obtains to remote powerful computer and obtains the resources on the machine.the resources on the machine.

FTP is the best protocol for file-transfer.FTP is the best protocol for file-transfer.– Understand Binary/ASCII, Client/ServerUnderstand Binary/ASCII, Client/Server

Discuss various kinds of Powerful tools Discuss various kinds of Powerful tools related to the Internet.related to the Internet.– Make good use of them.Make good use of them.– You can decide which of them you should You can decide which of them you should

install.install.



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ReferencesReferences

TucowsTucows Download.comDownload.com

The End.The End. Thank you for your patience!Thank you for your patience!

url, ftp & powertools csc1720 – introduction to internet essential materials

Documents

http http

url http

news http

uniform resource locators

internet resources web

major internet protocols

internet essential materials

url example