1 / 39

Working on Internet

Working on Internet. Chapter 15. Chapter Objectives. Describe Router Explain Network Address Translation (NAT) Explain Proxy Servers Configure TCP/IP Configure Internet Explorer Configure MS Outlook and Outlook Express Configuring DHCP,DNS, Host Names, FQDN, NETBIOS

townsend-maxim
Télécharger la présentation

Working on Internet

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Working on Internet Chapter 15

  2. Chapter Objectives • Describe Router • Explain Network Address Translation (NAT) • Explain Proxy Servers • Configure TCP/IP • Configure Internet Explorer • Configure MS Outlook and Outlook Express • Configuring DHCP,DNS, Host Names, FQDN, NETBIOS • Troubleshoot DHCP and DNS

  3. Recall • Simple Mail Transfer Protocol (SMTP) is an Internet standard protocol that is used for transferring email from one computer to another • File Transfer Protocol is used over the Internet to exchange files • Post Office Protocol version 3 (POP3) is an application layer Internet standard protocol used to retrieve email from a remote server to a local client over a TCP/IP connection

  4. Router • An Internetworking device used to link two different networks • Used to connect at least two networks and works at the Network layer • Forwards data packets across a network through a process called routing • Two types: • Static router - Needs to be configured manually • Dynamic routers - Does not require manual configuration

  5. Use of Router • Can be installed as an Internet gateway • Router is used to connect two networks for example WAN and LAN • Firewall are also provided by the router • Wireless networking is supported by few routers, which includes features like support for plug-n-play devices

  6. Network Address Translation (NAT) • Method in which a system’s IP address is changed into a different IP address before it’s sent out to an external network (Internet) • Enables the private network (Intranet) to use addresses that differs from the actual IP address on the Internet • Allows address hiding, thus it acts as a firewall • Web servers cannot be used as NAT clients • Provides a strong protection against unauthorized users

  7. NAT Advantages and Disadvantages • Advantages: • Hides internal structure of the network and increases network security • Allows unlimited class C network address • Helps in maintaining same internal network’s IP address when a computer is attached to the Internet • Disadvantages: • Changes IP addresses, thus troubleshooting becomes more complex • Blocks incoming connections

  8. A private (internal network) IP address is converted to a public IP address, which is always static (always remains same An internal network IP address is mapped to a registered IP address on one-to-one basis Static NAT

  9. An unregistered IP address is represented to a registered IP address from a set of registered IP addresses A computer with IP address 25.0.18.25 will translate to first available IP into a particular range for example from 28.35.15.100 to 28.35.15.125 Dynamic NAT

  10. Working of NAT • When packets of information are received from the outside network, NAT enabled router checks destination address and destination port on the packet • Router checks whether packet belongs to that network in translation table • Packet is rejected if it does not find any match in the translation table • Else router changes destination address to the one saved in address translation table and sends it to that computer • Computer receives the packet from the router

  11. Proxy Server • A computer that allows network users to make an indirect network connection to different network services • Used to configure Internet connection setting • Enhances the security for the user accessing the Internet and speeds up the Internet access by storing Web pages on the server

  12. Types of Proxy Servers • Transparent Proxies • Also known as forced proxy involves a combination of proxy server with NAT • Reverse Proxies • A reverse proxy server handles the request on behalf of the main Web Server • Anonymous Proxy server • Secure the user’s personal information by hiding the IP address

  13. NAT Vs. Proxy Server • Proxy server provides better performance through caching, for example caching of regular visited websites by the user • NAT is simple to configure, it doesn’t require additional software application • A proxy server is not transparent • NAT is transparent to the source and destination computers

  14. TCP/IP Configuration • Transmission Control Protocol/Internet Protocol is derived from two of the fundamental protocols, TCP and IP • Is a collection of networking protocols widely used on the Internet • TCP/IP is default Wide Area Network protocol • TCP/IP allows communication across various interconnected networks

  15. Basic TCP/IP ConfigurationParameters - I • Host name • Made up of letters, hyphen and numbers, begins with a letter • Not longer than sixty three characters • DHCP Client • DHCP is a TCP/IP service protocol • Offers dynamic leased configuration of host IP addresses

  16. Basic TCP/IP Configuration Parameters - II • IP address • Made of 32-bit binary number • Displays as four octets expressed in decimal and separated by periods • Domain name • A Domain is not a single computer, but a holding space into which a computer names can be added • A Unique name for example www.xyx.com • Made up of letters, hyphen and numbers

  17. Basic TCP/IP Configuration Parameters - III • Broadcast address • An IP address which enables information to be broadcasted to all computers on a subnet rather than only to a specific machine • Default router • A default router is the default gateway used by the device to access hosts on other networks • In a TCP/IP network, the nearest router to a particular host is known as default router

  18. Configuring Internet Explorer • Microsoft Internet Explorer is a web browser • Web browser enables to access the Internet • Internet Explorer is installed by default with the Microsoft Windows operating system • Internet Explorer settings can be modified to improve the Web page security and privacy

  19. Internet Explorer Security - I • Internet Explorer stores all the Websites into a single zone • By default, all the Websites are stored in the Internet zone

  20. Internet Explorer Security - II • Internet Zone • Consists of all Web sites that can be accessed by the computer • Local Intranet Zone • Includes allWebsites that reside on the user’s local network • Trusted Sites Zone • Includes the Websites that are safe • Restricted Sites Zone • Contains the Websites that are unsafe

  21. Case Study The Delhi branch of the MoneyMaker bank has marketing department which searches for new clients using different Web sites. The searches were performed in multiple ways such as using the search explorer bar, Web browser, search engine or address bar.

  22. Problem The default search action needs to be changed as per the requirements.

  23. Solution Change the default search actions.

  24. Configuring and Working with MS Outlook and Outlook Express • Microsoft Outlook is a software application for handling and organizing personal information • Microsoft Outlook is a stand-alone application that is a part of Microsoft Office • Outlook Express is a part of Microsoft’s Windows operating system • Outlook Express is an e-mail and news client

  25. MS Outlook • Offers e-mail service and comes under the category of e-mail client • Allows users to change the e-mail settings as per the user requirements • Compatible with other programs such as Microsoft Word

  26. Outlook Express • E-mail account in Outlook Express provides only e-mail and newsgroup functionality • Aimed at providing required services to home users • Exchange server and third party based accounts are not supported in Outlook Express

  27. Configuring DHCP Client • Configure client computers to receive IP addresses from the DHCP server • Any computer running a version of the Windows operating system such as Windows 2000, Windows XP and Windows NT can become a DHCP client • You can configure the client using the Internet Protocol (TCP/IP) Properties dialog box.

  28. Configuring DNS Client • DNS works at the application layer and uses Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) for transporting data over the network • DNS is configured so that it can resolve other computer names and IP addresses • You can configure the DNS client using the Internet Protocol (TCP/IP) Properties dialog box

  29. Host Names • Unique name by which a computer is known or recognized on a network • On a local area network, a hostname is commonly a single word • On the Internet, the host name is in the form "comp.abc.com” • Made up of lowercase letters and numbers

  30. FQDN (Fully Qualified Domain Name ) • A complete DNS name, including the host name and all of its domains (in order), is called a Fully Qualified Domain Name (FQDN) • Complete address of a site on the Internet • Consists of a host name and domain name, including top-level domain name • No two machines should have same Fully Qualified Domain Name

  31. Network Basic Input/Output System (NETBIOS) • A program that permits applications on different PCs to communicate within a Local Area Network • NetBIOS protocol is used when a user browses the network neighbourhood for any data on the network • Does not support a routing mechanism

  32. Troubleshooting DHCP • You can troubleshoot DHCP using: • Automatic Private IP Address (APIPA) • Used by clients, which are unable to access the DHCP server • A feature of Microsoft Windows Operating system • Always starts with 169.254.*.* • Releasing or Renewing IP address IPCONFIGis available with the release and renew options

  33. Troubleshooting DNS • DNS problems occur when there is a problem with the client system • You can troubleshoot DNS by: • Removing DNS cache – Use Ipconfig/flushdns • Name Server Lookup (Nslookup) - Allows querying DNS servers and obtaining detailed response at the command prompt

  34. Applications of Internet - I • Internet is basically network of networks • WebPages are viewed in web browser (Internet Explorer) through Internet • Applications: • WWW (World Wide Web) • E-mail (Electronic Mail) • FTP (File Transfer Protocol) • TELNET (TErminaL NETwork)

  35. Applications of Internet - II • WWW (World Wide Web) • Consists of WebPages • Contents of WebPages are links, text and graphics through which a user can access information from connected computer located at any part of the world • E-mail (Electronic Mail) • E-mail is source of information through which messages are sent and received via computer networks • E-mail can be sent to any user with a valid e-mail id

  36. Applications of Internet - III • FTP (File Transfer Protocol) • File Transfer Protocol is used to transfer information from the host computer to the server or vice versa • Separation of commands and data transfer makes FTP more efficient • TELNET (TErminaL NETwork) • Standard TCP/IP protocol for virtual terminal by ISO • General purpose client-server application program

  37. Summary - I • Router is an Internetworking device used to link two different networks • NAT is a method in which it translates system’s IP address to a public IP address before they pass through larger network or Internet • Proxy server allows network users to make an indirect network connection to different network services • Internet Explorer (IE) is the most widely used web browser

  38. Summary - II • MS Outlook is a part of Microsoft Office and acts as a personal information manager • MS Outlook offers e-mail service and comes under the category of e-mail client • Microsoft Outlook Express is an e-mail and news client • IP address can be allocated to a PC on boot process by a method called DHCP • DHCP offers dynamic leased configuration of host IP addresses and allots other configuration parameters to suitable network clients

  39. Summary - III • Individual computer names are called as host names in a network. A computer is known on a network by a unique name know as i.e. hostname • A complete DNS name, including the host name and all of its domains (in order), is called a fully qualified domain name (FQDN) • Network Basic Input/Output System is a program that permits applications on different PCs to communicate within a local area network • Internet also supports different format of information in form of text, graphics, audio, and video files which are displayed on the Web pages

More Related