Internet services

1
Internet services WWW

• Sadiq M. Sait, Ph.D
• sadiq_at_ccse.kfupm.edu.sa
• Department of Computer Engineering
• King Fahd University of Petroleum and Minerals
• Dhahran, Saudi Arabia

2

• Internet Services and Applications

3
What really is a Service?

• On internet (network of networks), computers
  communicate with one another. Users of one
  computer can access services from another.
• You can use many methods to communicate with a
  computer somewhere else on the Internet.
• These methods used to communicate are called
  services because they service your requests.
• There are a wide variety of services, and each
  can give you many kinds of information.
• In summary the internet is a
• way to move data
• a bunch of protocols

4
Available Services

• Some most popular services on the Internet are
• E-mail
• Telnet
• FTP
• WWW
• Others (Archie, Wais, Gopher, News and News
  Groups, Internet Relay Chat, Internet Phone,
  Video Conferencing, Internet Collaborative
  Tools)

5
Available Services (Contd.)

• Email Electronic mail
• Telnet Remote login into computer networks
• FTP File Transfer Protocol for transferring
  computer files
• WWW World Wide Web
• Gopher Searchable index, selectable index of
  documents
• USENET Newsgroups with different subjects enable
  people with common interest to share information
• Chat Real-time communications between people on
  the Internet

6
Clients and Servers

• All that we speak of internet fall into three
  categories
• Clients
• Servers
• Content
• Software/Hardware that we use to browse the web,
  send mail, download files, etc are called
  clients.
• Servers respond to clients requests.

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Internet Applications FTP and WWW
Client
FTP server
User
files
Internet
Browser
Helper Applications
Web Server
Binary Graphics Audio Video
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E-mail

• Most popular and widely used internet service.
• Has become a de-facto standard of communication
  within the corporate and beyond.
• Works between disparate systems like PC, Unix,
  Mac, etc.
• Latest e-mail standards let users attach files
  (audio, video, animation, etc).
• Volume of data transferred is billions of
  bytes/day.

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E-mail (Contd.)

• It is easy to send, read, reply to, and manage.
• It is convenient, global, economical and very
  fast.
• It has many advantages over regular methods such
  as postal service or fax technology.
• Studies have shown that recipients are more
  likely to reply to an e-mail message than a
  written request.
• E-mail can be read or written at any time,
  independent of time zones and business hours.

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E-mail (Contd.)

• Advantages
• Standard way of communication for corporations
• Less interference or interrupts between work
• Reply with a number of options
• No cost within the environment
• Less chance of miscommunication
• Can save messages for future retrieval and
  records
• Disadvantages
• You need to have a computer and a network
  connection
• Less personal than voice (although now we can
  also have voice mail, with some extra cost)

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How e-mail works?

• Like other internet services e-mail is yet
  another client-server system, called SMTP (simple
  message transfer protocol).
• You use a mail client program to send a message
  to the post office server (an SMTP server).
• The post office server identifies the recipients
  address and send the message through the internet
  to the mail server that handles mail for each
  recipients address.
• The mail server stores the message in the
  recipients mailbox.
• The recipient uses an e-mail client program to
  request new messages from the mail server.
• The mail server sends the message in the
  recipients mailbox back to the mail client.

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How e-mail works? (Contd.)

• Senders
• Mail
• Client

• Post OfficeServer
• (SMTP)

• MailServer(POP3)

• RecipientsMailClient

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How e-mail works? (Contd.)

• The Internet uses a TCP/IP-family protocol called
  Simple Mail Transfer Protocol (SMTP) as the
  standard method for transferring electronic mail.
• SMTP handles messages in queues (also called
  spools).
• When a message is sent to SMTP, it places it in
  an outgoing queue.

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How e-mail works? (Contd.)

• SMTP attempts to forward the message from the
  queue whenever it connects to remote machines.
• Usually, if SMTP cannot forward the message
  within a given amount of time, it is returned
  with an error message, or simply dropped.
• When a connection is established between two
  computers that use SMTP, the two systems exchange
  authentication codes.

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How e-mail works? (Contd.)

• Each system sends a command to the other to
  identify the first mail messages sender and
  provides basic information about the message.
• The receiving system returns an acknowledgement,
  after which the message is transmitted.
• SMTP is smart enough to handle multiple
  destinations for the same message in an efficient
  manner.

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Structure of Email

• A typical e-mail system, such as the one in a
  company office, usually consists of a mail
  server, a post office, and the clients.
• The mail system is tied directly to the local
  area network of the organization.

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Hotmail, Yahoo Mail, Rocket Mail .

• Hotmail and its cousins are all getting to be
  very popular because
• they offer free e-mail accounts,
• basically use Web-technology
• The disadvantage is that you have to
• wait longer frustrating experience if the mail
  is plenty and the lines are slow--which they are
  anyway, most of the time!
• The major advantage, however,
• is access to mail from virtually anywhere they
  can access the WWW on the Internet
• there is privacy, since mail is left on the server

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Finding an e-mail Address

• Finger and Whois
• Finger is a standard utility supplied with the
  TCP/IP protocol family that lets you determine
  who is a valid system user and who is logged into
  a system you have access to.
• Finger can be used to find out a persons
  username if a mail recipient is logged in on the
  destination machine.
• Finger shows you how long a user has been logged
  in, where theyre logged in from, and what their
  login names are.

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Mailing Lists

• A mailing list is a group of e-mail addresses
  that can be reached by sending a message to one
  address the list address.
• Mail sent to that address is redistributed to all
  subscribers.
• Subscribers can have a discussion by sending
  messages to the list address (often called
  posting to the list).
• The list of addresses can be maintained by hand
  or with an automated list server system like
  Majordomo or ListProcessor.

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Mailing Lists (Contd.)

• Mailing lists are good for many things such as
• distributing information from a central source to
  lots of people
• Discussing a project among participants.
• Exchanging questions and answers with other users
  of a product or service, or perhaps company
  technical-support personnel.
• To join just send mail to listserv_at_domain.name.
  where listserv is commonly the account through
  which messages are distributed

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TELNET

• Terminal Network Protocol
• Login to remote computer
• Usage of remote computer as if you were a local
  user
• An account on remote computer is required
• TELNET use
• Remote database access
• Remote access to remote customers computer for
  technical support

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TELNET (Contd.)

• Need to connect and log in to remote host
• Connect using host.domain telnet
  vlsi.ccse.kfupm.edu.sa
• Account userid must be known
• Password is usually required

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TELNET (Contd.)

• Weakness
• Only console applications can run. No GUI support
  unless X terminals are used.
• Security risk because hackers can trap the IP
  address of the network.
• Least used part of the Web
• All ports numbered 80 will have Web sites
  likewise all port 23s will be used for telnet,
  and multi-user games will always be found on
  4201, etc.

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FTP

• File Transfer Protocol
• Allows transfer of any type of file from the
  remote server to a local computer and vice versa
• Two types of FTP
• Secure FTP rarely used because of security
  issues
• Anonymous widely used
• Secure FTP Login to an account
• Access restrictions
• Passwords required

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FTP (Contd.)

• Anonymous FTP
• Provides unrestricted access to files and
  directories
• Examples free software, publications, press
  releases, etc.
• FTP use
• Distribution of software upgrades and new drivers
• Access to free information
• Access to free software and shareware

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Anonymous FTP

• They are called anonymous because they accept the
  word anonymous as a login name, and your
  e-mail address as the password.
• With this kind of service, you can download or
  upload files without having an account on the
  machine. Most often used to download files.
• If the FTP server isnt anonymous, when you
  connect to the server you must provide a user
  name and password, just as though you were
  logging in to the machine.
• Anonymous FTP servers are one of the major means
  of distributing software and information across
  the Internet.

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Anonymous FTP (Contd.)

• FTP servers are fairly straightforward. When a
  server receives a file request from an FTP
  client, it sends a copy of that file back to the
  client.
• Other commands instruct the server to send the
  client a directory of files, or to accept an
  upload from the client, etc.

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FTP

• A large amount of software, mostly free, is
  available on anonymous FTP servers for many
  different types of computer systems.
• One of the most frustrating problems with the
  Internet is the difficulty of finding information
  such as FTP sites, host resources, sources of
  information, and so forth.
• Most FTP sites dont have a listing of all their
  available files, although some do.
• However, if you have access to WWW, there are
  services (both free and fee-based) that provide a
  WAIS based search from inside a WWW browser,
  helping in locating information.

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FTP (contd.)

• Example FTP actions
• get Transfer a file from remote host to your
  computer
• put Transfer a file from your computer to remote
  host
• dir or ls Remote host directory listing
• ll or ldir Local directory listing
• chdir or cd Change remote directory
• lcd Change local directory

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Archie

• The archie service is a collection of resource
  discovery tools that together provide an
  electronic directory service for locating
  information in an Internet environment.
• Archie creates a central index of files available
  on anonymous FTP sites around the Internet.
• The Archie servers connect to anonymous FTP sites
  that agree to participate and download lists of
  all the files on these sites.
• These lists of files are merged into a database,
  which users can then search

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Archie (Contd.)

• Users can access an archie server either through
  interactive sessions or through queries sent via
  electronic mail messages.
• The archie server automatically updates the
  listing information from each site about once a
  month.
• In addition to offering access to anonymous ftp
  listings, archie also permits access to the
  whatis description database.

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WAIS

• WAIS stands for Wide Area Information Server and
  is pronounced ways.
• WAIS searches for words in documents.
• The core of the software is an indexer, used to
  create full-text indexes of files fed to it, and
  a server that can use those indexes to search for
  keywords or whole English expressions among the
  files indexed.

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Gopher

• The term Gopher refers to
• - A network protocol
• - A server type
• - One of the many Gopher client applications.
• Gopher protocol and software allow for browsing
  information systems so that one doesnt need to
  know exactly where the needed information is
  before looking for it.
• You do need to know the address of a Gopher
  server to get started, after you are there, the
  server software presents information in a clear,
  structured, hierarchical list.

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Gopher (Contd.)

• Most Gopher sites have links to others, so after
  connecting to one, it is quite easy to jump to
  another.
• Gophers user interface is very simple.
• Since the Gopher service is text-oriented, it
  performs well over slow links and can be used by
  people who only have dial-in access to a machine
  on the internet.

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Veronica

• Veronica is a service that provides a (very
  large) index of titles of Gopher items from most
  servers throughout the Internet.
• The result of a Veronica search is a set of
  Gopher items whose titles contain the keyword
  that the user was searching for.
• The Veronica index is accessed via a normal
  Gopher search item.

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News Newsgroups

• Network news is another way to take part in a lot
  of discussions over the internet, yet keeping
  them organized and separate from your mail.
• You dont have to subscribe to a mailing list,
  and you wont receive lots of mail.
• The news reader helps you keep everything in
  order.

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UseNet

• UseNet is a service carried over the Internet
  that supports newsgroups.
• The messages everyone using the UseNet sends to a
  newsgroup, become available for anyone who
  accesses the newsgroup.
• Newsgroups are organized hierarchically, with the
  broadest grouping first in the name.

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Newsgroups

• There are major news categories like
• comp, news, rec, sci, soc, talk, misc
• Servers can also get newsgroups by creating them
  locally.
• Server administrators can create whatever groups
  they like, corresponding to the interest of the
  users.

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News Item

• A news item is very similar to an electronic mail
  message.
• It has the same general parts as an e-mail
  message a header and a body.
• The body of a news item is the messages text.
• The header tells the news software how to spread
  the item throughout the Internet.

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Internet Relay Chat

• IRC (Internet Relay Chat) allows you to talk
  (write) to people from all over the world about a
  variety of topics, simultaneously and on-line.
• It is mostly used as a recreational communication
  system.
• It is again a client-server design.
• The client software allows you to connect to the
  IRC server, which accepts connections from many
  IRC clients at the same time.
• The various IRC servers across the Internet are
  interconnected.

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Internet Relay Chat (Contd.)

• There are a number of IRC servers running on the
  Internet, some of them are
• irc.netsys.com irc.caltech.edu irc.indiana.edu
  csa.bu.edu irc.nada.kth.se
• When you connect to an IRC server, you will
  usually be asked for a port number in addition to
  the Internet address.
• Most of the time, this port number is 6667
• Some IRC Terms Nicknames, IRC Channels

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Internet Phone

• Internet phones let you talk (literally talk,
  with voice not in writing) to people all over the
  world, just for the price of your Internet
  connection.
• It demands a reasonably fast machine with support
  for audio devices.
• Internet phones are essentially for
  point-to-point communications.
• The heart of any Internet phone tool is the
  codec, the software that compresses/decompresses
  the digitized voice data
• Most Internet Phones offer more than just
  telephony, e.g., voice mail, answering machines,
  and similar features.

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Video Conferencing

• Internet Video Conferencing offers a low-cost
  alternative to traditional proprietary systems.
• It demands high bandwidths.
• It requires a video camera and related hardware
  card.
• Video-conferencing is largely point-to-point.
• Only very few packages support true
  multi-conferencing.

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Introduction to WWW

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Introduction to WWW

• WWW Terminology
• Web page design and HTML (Basics)
• Web Client/Server Software and HTTP
• Images, Image maps, forms, and frames
• Web authoring and Database integration
• Search engines
• Dynamic HTML, VRML, etc
• Advanced topics and much more

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Lingo

• HyperText Enables linking to places
• Link(s)
• Hyperlinks Hot spots on which a user can click
  to access other
• topics (in the same document)
• documents, (other HTML files, for e.g.),or
• Web sites
• URL Addresses on Internet to which hot spots
  connect

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Lingo (contd.)

• GIF, JPEG, XBM, XPM (picture formats)
• Netscape, Mosaic, Iexplorer (browsers)
• WebEdit, HoTMetaL, FrontPage (editors/tools)
• FTP, TCP/IP, HTTP (protocols)
• Applets, J, javac, Java Engine (Java
  programming)
• xv, clipart, etc (graphics editors)

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Why Design and for Who?

• Personal Pages
• Companies, Organizations
• (schools, universities, research centers, etc)
• News Networks
• Journals
• Events (conferences, international games, etc)
• Internet/Intranet

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What in this session?

• WWW, HTML, and HTTP
• HTML Document structure
• Hyperlinks, Images, Multimedia
• Tools for creating HTML
• Beyond simple HTML (Advanced tags, dynamic HTML,
  VRML, etc..)
• Other recent technologies (Push technology,
  e-commerce, search engines..)

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A Brief overview of HTML?

• HTML is a structured language
• rules of nesting
• All WWW documents are written in HTML
• WWW
• World Wide Web
• Most popular Internet information service

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Web Usage?

• It was estimated that of the 28.8 million people
  over 16 in the US who have internet access, 11.5
  million use the web (1996).

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World Wide Web

• Client/Server Architecture
• Designed to make it easy for people to share
  information
• Hides complexities of location of documents
• Easy to distribute information
• Fun to look at

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World Wide Web

• Hyperlinks
• Highlighted words or pictures
• Item pointed to may be another document image,
  movie, sound clip etc

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Example
Visit NYSE
city tours
NY CITY TOURS
NYSE sounds
view sights
Movie
sound audio
55
WWW Browsers

• Interpret HTTP as well as other protocols
• ftp, mailto, telnet, gopher, etc.
• Display physical formatted HTML text
• in-line images
• hyperlinks

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WWW Browsers

• Helper Applications
• Programs on the users computer that can be used
  to display images, movies, sound, etc. that
  cannot be displayed on the browser itself
• Sound files
• Movies (MPEG)
• Mail
• Other file formats

57
Some Recent Additions

• Common Gateway Interface
• ASP
• Helper Programs and Plugins
• JavaScript and VBScript
• etc

58
Why Learn?

• Why learn HTML or Web Authoring?
• Everyone is a publisher
• The architecture of the Internet allows almost
  anyone to become an information provider for a
  world wide audience
• WWW documents must be in HTML
• To create your own home page you need to know
  some HTML or Web authoring tool

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Why learn HTML?

• Not a must
• Can use tools to create HTML (FrontPage98)
• Conversion tools can be used to convert existing
  HTML documents
• Example LaTeX2HTML
• Word documents can be saved in HTML
• FrameMaker documents too
• It is very easy to learn and understand

60
Creating an HTML Page

• Requirements
• Text or HTML Editor to enter TAGS
• Graphics editors
• Browser (Netscape, Internet Explorer, Lynx,
  etc.)
• Focus
• Usable and Eye-catching documents
• Images in Web pages
• Animation

61
HTML Basics

• HTML documents contain 3 things
• Text TAGS
• External Multimedia such as graphics, sound,
  movies, etc.
• Authoring tools insert necessary tags

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What are Tags?

• Tags are needed to
• Mark text as headings, paragraphs, for
  formatting, making list etc.
• Also for creating hyperlinks, including images,
  making tables, fill-in forms, frames, etc
• Examples ltPgt, ltAgt, ltBRgt, ltHRgt, ltFONTgt, ltBgt,
  ltTTgt, ltEMgt, ltULgt, ltIMGgt, etc.

63
HTML Document Structure

• Basic Structure
• ltHTMLgt
• ltHEADgt
• ltTITLEgt KFUPM lt/TITLEgtlt/HEADgt
• ltBODYgt
• .. ..
• lt/BODYgt
• lt/HTMLgt

64
Spinning your HTML Web

• To create hot spots (or Anchors) you need two
  things
• URLs (Uniform Resource Locator)
• Links
• Anchors and Links allow readers to jump from
  place to place in the document
• URL is a fancy way of saying address or location
  for information on the Internet

65
URL Anatomy Types

• Example
• http//www.ccse.kfupm.edu.sa/sadiq/tut.html
• protocol indicator,hostname,directory/filename
• Types
• Absolute URLs (also called complete URLs)
• Relative URLs (are incomplete URLs)
• Other Protocols (mailto, ftp, etc)
• ftp//ftp/pub/images/backgrounds/glosbgr.gif
• mailtosadiq_at_ccse.kfupm.edu.sa

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Examples

• http//www.ccse.kfupm.edu.sa/sadiq/tut.html
• ltIMAGE SRC ftp//ftp/pub/images/backgrounds/glosb
  gr.gif ALIGN MIDDLEgt
• ltA HREF
• mailtosadiq_at_ccse.kfupm.edu.sagt
• sadiq_at_ccse.kfupm.edu.salt/Agt

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Building Anchors ltAgt

• Components required
• The Tag ltAgt anchor_name lt/Agt
• HREF Indicates where to jump
• NAME Identifies an internal label
• HREF Lets users jump to either material on the
  same Web site or to other material on the
  Internet
• NAME Lets users jump to material within the same
  document

68
Named Anchor Basic Links

• ltA HREFsomethinggtanchor_name lt/Agt
• something name
• namefunny (for example)
• something filename.htmlname
• tutorial.html
• something a Web site, for example
• http//www/uqu.edu.sa/youssef/tutorial.html
• ftp//www/ksu.edu.sa/ahmed/jokes.html
• ltH2gtltA NAMEfunnygt Funnylt/Agtlt/H2gt

69
Using Images in Web Pages

• Including
• Aligning
• Using them as links
• Making images load more quickly
• Using thumbnail images

70
Adding Images

• Must include them as GIF or JPG graphics
• Use graphic editors, scanners, or, borrow
• Must use an Image Tag ltIMG SRC "..gt
• ALT". . . " specifies text to be displayed if
  image not available
• BORDER of pixels, controls the thickness of the
  border
• Pictures can be aligned Left, Right, etc.

71
Example of Image Inclusion

• ltHTMLgt
• ltHEADgtltTITLEgt Biography lt/TITLEgtlt/HEADgt
• ltBODYgt
• ltH1gt Dr. Sadiq M. Saits Biography lt/H1gt
• ltPgtltIMG SRC"sadiq.gif"
• ALT"Picture of Sadiq Sait " ALIGNRIGHTgt
• Picture of Sadiq M. Sait for his biography...lt/Pgt
• lt/BODYgt
• lt/HTMLgt

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Some notes on Images

• Loading of images is made faster by telling the
  browser the size of the image (specified in
  pixels)
• You can link by using images
• Can have pictures with no borders
• You can use thumbnail images to link to larger
  images
• Making clickable images (image maps)

73
Pictures as Links

• ltPgt
• ltA HREF"saitbio.html"gt
• ltIMG SRC"sadiq.gif"
• ALT"Picture of Sadiq Sait" ALIGNRIGHT
• HSPACE20 HEIGHT100 WIDTH50
• BORDER0gt
• lt/Agt
• Sadiq M. Sait was born in ......lt/Pgt

74
Using Thumbnails

• ltPgt
• ltA HREF"sadiqbig.gif"gt
• ltIMG SRC"sadiqthumbnail.gif"
• ALT"Picture of Sadiq Sait"gt
• lt/Agt Thumbnail of Saits picture.

75
Defining the map

• Tells which area readers may click and what link
  to follow
• ltMAPgt
• NAME gives the map a name
• ltAREAgt specifies the shape of a hot spot
• COORDSx1,y1,x2,y2,
• HREFURL
• SHAPE specifies type of shape as RECT, CIRC,
  POLYGON, etc.

76
Other Attributes

• Choosing Colors
• Background
• Links (link, alink, vlink)
• Text
• Colors can be chosen for tables, background etc.
• RGB concept (FFFFFFwhite)
• Choosing background (using images, .gif files)

77
Beyond Simple HTML

• Tables
• Forms
• Frames
• Simple animation
• Inclusion of Java Applets
• JavaScript and CGI programs

78
Some More Tags

• CENTER, BLINK, HR, APPLET
• ltFORMgt
• SELECT, OPTION, TEXTAREA
• ltTABLEgt
• TR, TH, TD, CAPTION
• FRAME
• FRAMESET
• And many more.

79
Tables in HTML

• Caption
• Alignment and Width
• Table Header ltTHgt
• Table Data ltTDgt
• Table Rows ltTRgt
• Color (of cells)
• Border or not (and width)

80
Tables (example)

• ltTABLE BORDER10
• ALIGNABSCENTER bgcolor68d1ccgt
• ltCAPTIONgtltH3gt This is a table with a borderlt/H3gt
  lt/CAPTIONgt
• ltTRgt ltTHgt ltTHgtMale ltTHgtFemale ltTRgt
  ltTHgtPop ltTDgt0.49ltTDgt0.51 ltTRgt ltTHgtWealth
  ltTDgt 0.9ltTDgt 0.1
• lt/TABLEgt

81
Forms in HTML

• What are they used for
• Surveys
• Collect addresses of visitors to your Homepage
• Allow people to register for something
• Features
• Submitted by mail
• Security (Passwords)
• Checkboxes and Radio buttons
• Area for Text and Comments
• Require a CGI program on server to process data
  coming from the form submission

82
Frames

• SRC URL of documents to be displayed
• NAME so this frame can be targeted by links in
  other documents
• Physical dimensions Height, width etc.
• Other features Scrolling, Resizing, etc.
• They are a complete HTML document or a page

83
Spicing up your Web Page

• Some HTML commands and Tricks
• BLINK tag, etc
• Animation (GIF animation) and Sound
• Using Java Applets
• Scripting (JavaScript/VBScript)
• Videostreaming

84
Java Applet inclusion

• Compile the Java code (e.g., use javac)
• example javac Blinker
• Creates file with extension .class,
• example Blinker.class
• Use the tags ltAPPLETgt lt/APPLETgt
• Specify parameters such as speed, color (for
  background and text, etc.)

85
Java Applet Inclusion (contd.)

• ltapplet codeBlink.class width300 height30gt
• ltparam namelbl value SADIQ M. SAIT,gt
• ltparam namespeed value6gt
• lt/appletgt

86
Java Applet Inclusion (contd.)

• ltapplet codeticker.class width280 height30gt
• ltparam namemsg value Welcome to the tutorial
  on Web page design and HTML! gt
• ltparam nameshco value210, 210,210gt
• ltparam namespeed value9gt
• ltparam namebgco value255,255,255gt
• ltparam nametxtco value255,0,0gt
• lt/appletgt

87
Other Topics

• cgi-bin (common gateway interface)
• Executable Example
• lt!--exec cgi/cgi-bin/counter--gt people
  visited this page.
• Helper programs
• to send mail
• run audio/video applications
• etc

88
Searching

• On the internet we can
• search for a file using Archie
• Find an e-mail address
• Internet White Pages (internic keeps records)
• Finding a gopher site
• etc
• Search engines using the Web

89
Search Engines

• Tools to discover Web resources on the internet
• Help in locating information
• They act as an agent between publishers and users

90
Other Recent Technologies

• Authoring Tools
• VRML, Dynamic HTML, ASPs, etc
• Video Streaming
• Push Technology
• Data-Base Integration
• Search Engines
• E-Commerce

91
Finally.

• Summary
• Demo