Jordan University of Science & Technology Faculty of Computer & Information Technology Department of Computer Science CIS 100 Internet 1 What is Internet? Internet is a global computer network of interconnected networks. 2 Internet Activities 1. All computers connected to the internet must 2. 3. 4. 5. communicate with each other using set of rules (protocols) called TCP/IP (Transmission Control Protocol/ Internet Protocol) Send and receive electronic messages (e-mail) Transfer data files to and from computers around the world (File Transfer Protocol [FTP]) View corporate or personal documents containing graphical hypertext content (World Wide Web) Share point-of-view on specific subjects with other online groups, (Usenet news-groups - Network News Transfer Protocol) 3 Internet Addressing Each computer directly linked to the Internet must obtain a unique address so that it can be located. A computer’s internet protocol (IP) address is a fourpart series of numbers separated by periods. For example 198.137.241.30 Because it is difficult to remember a long series of numbers( i.e. IP address ), a name addressing system was developed, called domain name system (DNS), For example Whitehouse.gov The DNS: is a world-wide system of databases that maps domain names with their corresponding IP address. 4 How To Get Internet Connection? To obtain an Internet domain name, It is necessary to register with (and pay) a special Internet committee, Internet Service Provider (ISP) ISP examples: ORANGE, Batelco, TE Data, and Zain To get internet service: Subscribe with any Internet Service Provider (ISP) 5 Site Types The top-level specification: .com: commercial organization. .edu: education. .int: international organization. .mil: military organizations. .org: nonprofit and research organizations. .net: network and service operations. 6 Country Code Two-letter country code: .us: United States. .jo: Jordan. .uk: United Kingdom. 7 Domain Name Second-level domain name (it is the company or organization name): up to 22 alphanumeric characters and cannot include spaces (although underscore can be used). examples of the Domain name: www.example.net www.yahoo.com www.hotmail.com The alphanumeric character set consists of the numbers 0 to 9 and letters A to Z. 8 Subdomain Name Subdomain Name: Put it to the left of the domain name We may have additional subdomain names It is optional part Subdomain Name examples: www.cis.just.edu.jo www.mail.yahoo.com 9 Domain, LAN, and Network Server This entire domain is part of LAN connected to the internet. The network server is connected to the Internet. So each of the computers on the network gain their access to the Internet through the network server. LAN: Local Area Network Hostname: i.e. the Host Computer 10 What is the World Wide Web? The World Wide Web is a collection of host machines: which deliver documents, graphics and multi-media to users via the Internet. 11 World Wide Web Pages or files are stored on Web Servers. Users access these pages using a graphical browser like: Internet Explorer Netscape Communicator Pages can include: Graphics, sound, movies and other media-rich content References to other pages on the same site or other sites 12 Hyper-Links A hyperlink is a clickable link to another document or resource. It is normally shown in blue underline. When a user clicks on this link The client will retrieve the document associated with that link by requesting the document from the designated server upon which it resides. 13 URLs An URL (Uniform Resource Locator) is a means of specifying the pathname for any resource on the Internet. The URL consists of three part: 1. 2. 3. protocol part host part document name 14 URLs Example http://www.just.edu.jo/cis100/windows.htm specifies the protocol as http, the host or WWW server as just.edu.jo and the document as /cis100/windows.htm 15 Search Engines Because there is so much information available on the Internet today so: it is important to be able to access information quickly. Several sites have specialized in searching Search Engines Examples: www.yahoo.com www.google.com www.excite.com www.metacrawler.com 16 Browsing the Web The features of World Wide Web (WWW) are: server provides WWW access information presented as pages uses html (hyper-text markup language) to write pages pages may reference other pages, graphics etc (links) client provides browse services to view pages and handle special page types connect only long enough to get a page Examples of available browsers include Netscape Communicator and Internet Explorer. 17 HTML HTML: Hyper Text Markup Language. Used to create (design) Web pages which may include: Text, graphics, sound, video and/or links to other pages 18 Web Browser A WWW browser is an application run on a user’s computer which allows him to view the pages made available by a WWW server The browser interprets each HTML page and displays the information in a window. Each WWW server has a host name, and each page has a location address where it resides on the server. 19 Example http://www.just.edu.jo/index.htm The site-name is www.just.edu.jo which denotes the server address for the WWW server at JUST The page, which is shown as JUST’s home page is called index.htm 20 Electronic Mail (email) Electronic mail, or email, is: a simple tool for exchanging messages between individuals or among larger audience. 21 Electronic Mail Email messages travel very quickly and inexpensively The delivery of messages from one part of a country to another may take minutes Once a message has been received, it can be saved, printed, edited, forwarded to another user, or deleted Email is becoming one of the most widely used services on the Internet: 22 Email Characteristics Email is becoming one of the most widely used services on the Internet : 1. Fast 2. Can save messages for future reference. 3. Free of charge. 23 How to get email account ? How to get just email? From the University (Engineering Building, C3- level 1 ?) Get a free web-based email account through yahoo or Hotmail 24 Email Address An email address has two parts: 1. Username 2. Domain Name Email Address Example: ahmad@just.edu.jo 25 Email Message’s Parts An email message must have at least two parts: 1. Header 2. Body 3. Message Signature (optional) 26 Email Message’s Parts 1. The Message Header contains information about the message: sender, receiver, date and subject 2. 3. CC : Carbon Copy BCC: Blind Carbon Copy The Message body contains the actual message being sent Message Signature (optional) (see next slide) 27 Message Signature Sometimes, an email message contains a third part, called the signature It is optional, and usually identifies or provides information about the message’s sender 28 Review CC : Carbon Copy BCC: Blind Carbon Copy Protocols: set of rules TCP/IP :Transmission Control Protocol/ Internet Protocol) File Transfer Protocol [FTP] use to: Transfer data files to and from computers around the world? internet protocol address : IP address DNS: it is a name addressing system was developed, called domain name system (DNS) URL: Uniform Resource Locator HTML: Hyper Text Markup Language 29