A+ Guide to Managing and Maintaining your PC, 6e

Chapter 10…..

PCs on the Internet

Objectives

• Learn about the TCP/IP suite of protocols • Learn how to connect to the Internet using cable modem, DSL, and dial-up connections and how to share those connections • Learn how to use a router to enhance and secure a network connection to the Internet • Learn about supporting common Internet clients such as Web browsers, e-mail clients, file transfer software, Internet telephone, and Windows XP Remote Desktop A+ Guide to Managing and Maintaining your PC, 6e 2

Introduction

• Topics to cover – How the TCP/IP suite of protocols is used – Creating and troubleshooting broadband connections – How to create and troubleshoot dial-up connections – How to install and use a router – Supporting Internet applications; e.g., Web browsers A+ Guide to Managing and Maintaining your PC, 6e 3

The TCP/IP Suite of Protocols

• Client/server application – Client application on one PC requests data from server – Server application on another PC returns data • Example: World Wide Web – The client is a Web browser – The server is a Web server; e.g., Apache HTTP server – Requested data is a Web page • Client applications are installed as programs • Server applications are installed as services A+ Guide to Managing and Maintaining your PC, 6e 4

Figure 18-1

A Web browser (client software) requests a Web page from a Web server (server software); the Web server returns the requested file or files to the client A+ Guide to Managing and Maintaining your PC, 6e 5

Using IP and Port Addresses to Identify Services

• Port (port address, port number) – Number that identifies server application to client – Server application listens for request at assigned port – Example: port 80 is typically assigned to Web servers • Port numbers appear at the end of an IP address – Example: 138.60.30.5:80 • A few other common ports and assigned services – Port 20: FTP (File Transfer Protocol) – Port 25: E-mail (using SMTP protocol) – Port 443: Web server (using HTTPS protocol) A+ Guide to Managing and Maintaining your PC, 6e 6

Using IP and Port Addresses to Identify Services (continued)

• Communication protocol – Defines rules of communication between client/server – Example: POP3 is used by client to receive e-mail • Information flow between client and server – Application sends request to OS – OS passes request to NIC – NIC places request on network – NIC on receiving end sends request to OS – OS passes request to Web server application – Web server responds by sending data to OS A+ Guide to Managing and Maintaining your PC, 6e 7

Common Port Numbers

• http://www.answersthatwork.com/Download_Area/ ATW_Library/Networking/Network__2 List_of_Common_TCPIP_port_numbers.pdf

A+ Guide to Managing and Maintaining your PC, 6e 8

TCP/IP Packet

A+ Guide to Managing and Maintaining your PC, 6e 9

Figure 18-3

Applications, operating systems, and the physical network manage communication at all three levels A+ Guide to Managing and Maintaining your PC, 6e 10

TCP/IP Protocol Layers

• TCP/IP suite lies between applications and the OS • API: application programming interface • How application protocols are used – Application makes an API call to the OS – The API causes OS to generate a request • Request follows format specified by application protocol – After response is passed back, a session is established • Example involving HTTP (Hypertext Transfer Protocol) – Web browser makes an API call to the OS – OS makes an HTTP request for a browser A+ Guide to Managing and Maintaining your PC, 6e 11

Figure 18-4

How software, protocols, and technology on a TCP/IP network relate to each other A+ Guide to Managing and Maintaining your PC, 6e 12

TCP/IP Protocol Layers (continued)

• Transmission Control Protocol (TCP) – A connection-oriented protocol – Makes a connection, checks delivery, resends data • User Datagram Protocol (UDP) – A connectionless or best-effort protocol – Does not guarantee delivery • Internet Protocol (IP) – Breaks up and reassembles data into packets – Routes packets to their destination • TCP uses IP to establish session and verify delivery A+ Guide to Managing and Maintaining your PC, 6e 13

Figure 18-5

TCP turns to IP to prepare the data for networking A+ Guide to Managing and Maintaining your PC, 6e 14

TCP/IP Protocol Layers (continued)

• ARP (Address Resolution Protocol) – Responsible for locating a host on a local network • RARP (Reverse Address Resolution Protocol) – Discovers Internet address of host on a local network • ICMP (Internet Control Message Protocol) – Communicates problems with a transmission – Example: message deleted due to excessive hops • Network protocols used by hardware – Ethernet and PPP (Point-to-Point Protocol) A+ Guide to Managing and Maintaining your PC, 6e 15

TCP/IP Utilities

• TCP/IP component includes a group of utilities – Location: Windows or \Winnt folder • Commonly used utilities: Ping, Winipcfg, Ipconfig • SNMP (Simple Network Management Protocol) – Provides system management tools for networks • Microsoft SNMP Agent – Utility installed after TCP/IP is installed – Used to monitor remote connections • Tracert (trace route): shows hops along packet route A+ Guide to Managing and Maintaining your PC, 6e 16

Figure 18-9

The Tracert command traces a path to a destination computer A+ Guide to Managing and Maintaining your PC, 6e 17

Connecting to the Internet

• Broadband: supports multiple transmission types • Internet Service Provider (ISP) – Connects a PC or network to the Internet • Bandwidth technologies used by ISPs: – Regular telephone lines – Cable modem – DSL (Digital Subscriber Line) – ISDN (Integrated Services Digital Network) – Satellite access – Wireless access A+ Guide to Managing and Maintaining your PC, 6e 18

Cable Modem and DSL Connections

• Comparing communication media – Cable modem: TV cables shared by multiple users – DSL: dedicated phone lines • Comparing service plans – Both: sliding-scale residential and business plans • Comparing setup – Both: a modem interfaces PC and broadband jack • Comparing installation services: – Both: will install equipment at additional cost A+ Guide to Managing and Maintaining your PC, 6e 19

Figure 18-10

Cable modem connecting to a PC through a network card installed in the PC A+ Guide to Managing and Maintaining your PC, 6e 20

Cable Modem and DSL Connections (continued)

• Overview of installing cable service or DSL – Connect the PC to the cable modem or DSL box – Connect cable modem/DSL box to broadband jack – Plug up power and turn on the broadband device – Configure TCP/IP settings for connection to the ISP – Test connection by using a browser to surf the Web • Devices and information needed for an installation – A computer with an available network or USB port – Modem/box and network cable – TCP/IP settings A+ Guide to Managing and Maintaining your PC, 6e 21

Figure 18-18

Sample setup for DSL A+ Guide to Managing and Maintaining your PC, 6e 22

Dial-Up Connections

• Based on a modem and regular phone line • How dial-up networking works – TCP/IP creates data packets for transport – PPP adds its own header and trailer to data packets – PPP presents packet to modem for delivery on line – Process is reversed when data packet is received • Overview of setting dial-up in Windows XP – Install an internal or external modem – Launch New Connection Wizard – Follow directions onscreen A+ Guide to Managing and Maintaining your PC, 6e 23

Figure 18-19

PPP allows a PC to connect to a network using a modem A+ Guide to Managing and Maintaining your PC, 6e 24

Figure 18-21

The New Connection Wizard asks how to configure the connection A+ Guide to Managing and Maintaining your PC, 6e 25

Dial-Up Connections (continued)

• A few troubleshooting tips – Plug in a regular phone and check line for a dial tone – Try another phone number – Reboot your PC and try again • Overview of setting dial-up in Windows 9x/Me – Dial-Up Networking must first be installed • A dial-up adapter will also be installed – Install an internal or external modem – Create connection with Make New Connection Wizard – Configure the connection from Properties dialog box A+ Guide to Managing and Maintaining your PC, 6e 26

Figure 18-27

Configuring the server type for a connection to the Internet in Windows 9x/Me A+ Guide to Managing and Maintaining your PC, 6e 27

Dial-Up Connections (continued)

• High-speed dial-up: reduces download time by half • Enhancements needed to support high-speed dialup – Abbreviated handshake – Data compression – Filtering – Server-side caching – Client-side caching A+ Guide to Managing and Maintaining your PC, 6e 28

Figure 18-30

Server-side caching and client-side caching improve download times by reducing the number of requests for data A+ Guide to Managing and Maintaining your PC, 6e 29

Sharing a Personal Internet Connection

• Networked PCs access Internet through a host • Connecting two PCs – Single crossover network cable links two PCs – Host PC connects to the modem • Connecting three or more PCs – PCs connect to hub/switch using patch cables – Host connects to modem via USB cable • Internet Connection Sharing (ICS) – Manages shared Internet connections – Enables host to use NAT and act as proxy server A+ Guide to Managing and Maintaining your PC, 6e 30

Figure 18-31

Two or more networked computers can share a single Internet connection A+ Guide to Managing and Maintaining your PC, 6e 31

Network Address Translation

A+ Guide to Managing and Maintaining your PC, 6e 32

Implementing a Software Firewall

• Guidelines for protecting your PC – Keep Windows updates current – Use a software or hardware firewall – Run antivirus software and keep it current • Services provided by a hardware or software firewall – Firewalls can filter data packets – Firewalls can filter ports – Firewalls can block certain activity within the network – Firewalls can filter inappropriate information • Example of a software firewall: Windows Firewall A+ Guide to Managing and Maintaining your PC, 6e 33

Figure 18-34

Windows Firewall is set for maximum protection A+ Guide to Managing and Maintaining your PC, 6e 34

Using a Router on Your Network

• Disadvantages of using a host to share a connection – Host computer must always be turned on – Only low-level security for your network – Bottlenecks at host can slow traffic within network • Solution: use a router to interface with the Internet • Router provides two functions – Takes place of host as gateway to the Internet – Serves a hardware firewall to protect your network A+ Guide to Managing and Maintaining your PC, 6e 35

Figure 18-36

A router stands between the Internet and a local network A+ Guide to Managing and Maintaining your PC, 6e 36

Advantages of Using a Router

• Host PC will not be a performance bottleneck • Internet access is not dependent on running host • Router can also serve as a hardware firewall • The router can provide additional features – DHCP server, switch, or wireless access point • Example: Wireless-G Broadband Router by Linksys A+ Guide to Managing and Maintaining your PC, 6e 37

Figure 18-37

This Linksys router allows computers on a LAN to share a broadband Internet connection and is an access point for computers with wireless adapters A+ Guide to Managing and Maintaining your PC, 6e 38

Installing and Configuring a Router

• Run the setup program on any network PC • Connect the cable or DSL modem to the router – Follow the instructions on the setup screen • Connect PCs on your network to your router – PC can connect directly to a network port – You can also connect a switch or hub to the router • Plug in the router and turn it on • Sign in with default password and then reset it A+ Guide to Managing and Maintaining your PC, 6e 39

Installing and Configuring a Router (continued)

• Configuring a router (using Linksys as an example) – Access configuration program on router firmware • Enter the IP address of the router (192.168.1) – View and/or change default settings in Setup window • Configure a hardware firewall – Settings in Security tab and Access Restrictions tab • Port filtering: open or close certain ports for use • Port forwarding – Request to certain ports forwarded to certain PCs – Local PC must have static address for this service A+ Guide to Managing and Maintaining your PC, 6e 40

Figure 18-39

Basic Setup screen used to configure the router A+ Guide to Managing and Maintaining your PC, 6e 41

Figure 18-42

With port forwarding, a router allows requests initiated outside the network A+ Guide to Managing and Maintaining your PC, 6e 42

Virtual Private Network

• How VPN security works – Remote user sends id to authentication server – Authentication server encrypts data • Various encryption protocols are used; e.g., CHAP – Tunnel is created so all data transferred is encrypted • Various tunneling protocols are used; e.g., PPP • How to configure a router to support VPN – Select encryption and tunneling protocols – Configure each tunnel the VPN will support • Configure client for VPN from Network Connections A+ Guide to Managing and Maintaining your PC, 6e 43

Figure 18-45

With a VPN, tunneling is used to send encrypted data over wired and wireless networks and the Internet A+ Guide to Managing and Maintaining your PC, 6e 44

Figure 18-48

Properties window of a VPN connection A+ Guide to Managing and Maintaining your PC, 6e 45

Supporting Internet Clients

• Section task: support Internet clients • Common Internet clients – Web browsers – E-mail – FTP – VoIP – Windows XP Remote Desktop A+ Guide to Managing and Maintaining your PC, 6e 46

Supporting Web Browsers

• Web page: text file with an .htm or .html extension – Coded in HTML (Hypertext Markup Language) • Web browser: requests pages from a Web server • Uniform Resource Locator (URL): Web page address • Components of a URL – Protocol, host name, network name, folder, file name – Domain name = host name + network name – Example: http://www.course.com/myfolder/myfile.html

• Name resolution service relates name to IP address A+ Guide to Managing and Maintaining your PC, 6e 47

Figure 18-49

A URL contains the protocol used, the host name of the Web server, the network name, and the path and filename of the requested file A+ Guide to Managing and Maintaining your PC, 6e 48

Table 18-3

Suffixes used to identify top-level domain names A+ Guide to Managing and Maintaining your PC, 6e 49

Supporting Web Browsers (continued)

• Examples of Web browser software – Firefox by Mozilla, Internet Explorer (IE) by Microsoft • Some configuration tasks you can perform in IE – Configure the pop-up blocker – Manage IE add-ons – Set Internet Explorer security levels – Control how and if scripts are executed – Configure ActiveX controls – Control proxy settings A+ Guide to Managing and Maintaining your PC, 6e 50

Figure 18-53

Set the security level of Internet Explorer using the Internet Options window A+ Guide to Managing and Maintaining your PC, 6e 51

Supporting Web Browsers (continued)

• Solving Internet Explorer problems – First perform routine maintenance; e.g., run ScanDisk – Clean out cache that IE uses to hold temporary files – Suppress downloading images – Repair a corrupted Internet Explorer cache – Run antivirus software – Update Internet Explorer – Verify Windows system files using System File Checker – Remove and reinstall Internet Explorer 6 A+ Guide to Managing and Maintaining your PC, 6e 52

Figure 18-56

Use the Internet Options window to control the Internet Explorer environment A+ Guide to Managing and Maintaining your PC, 6e 53

Supporting Web Browsers (continued)

• Digital certificate: identification plus public key • SSL (Secure Sockets Layer) – Encryption system using a digital certificate – Data is encrypted with public key – Data is decrypted with a private key • TLS (Transport Layer Security) – An improved version of SSL • HTTPS (HTTP secure) – Can mean HTTP over SSL or HTTP over TLS – Indicates secure protocol being used is SSL or TLS A+ Guide to Managing and Maintaining your PC, 6e 54

Figure 18-61

Using secure HTTP, a Web server and browser encrypt data using a public key before the data is transmitted A+ Guide to Managing and Maintaining your PC, 6e 55

Supporting E-mail

• SMTP: Simple Mail Transfer Protocol • SMTP AUTH (SMTP Authentication): improved SMTP • POP: Post Office Protocol • IMAP4: Internet Message Access Protocol, version 4 • Route traveled by e-mail – Client sends e-mail to client e-mail server using SMTP – Client e-mail server sends e-mail to recipient with SMTP – Recipient’s e-mail server forwards e-mail to recipient • Recipient’s e-mail server uses POP or IMAP4 • Recipient must first login and request e-mail from server A+ Guide to Managing and Maintaining your PC, 6e 56

Figure 18-63

The SMTP protocol is used to send e-mail to a recipient’s mail server, and the POP3 or IMAP4 protocol is used to download e-mail to the client A+ Guide to Managing and Maintaining your PC, 6e 57

Supporting FTP

• File Transfer Protocol (FTP) – Used to transfer files between two computers • FTP server (or FTP site) – Application running on another server; e.g., Unix server • FTP from a command prompt – Connection to a network must first be established – Some commands: FTP, get yourFile.dat

• File transfer using FTP software – FTP utility software: can be downloaded from Internet – Web browser: change protocol used in address bar A+ Guide to Managing and Maintaining your PC, 6e 58

Figure 18-68

Using Internet Explorer as an FTP client A+ Guide to Managing and Maintaining your PC, 6e 59

Supporting VoIP

• VoIP (Voice-over-IP) – Provides voice communication over a network • Two types of phones used in VoIP service – Digital telephone: plugs into a network port – Analog phone: needs Analog Telephone Adapter (ATA) • Special requirements of VoIP – Phones must be assigned number by VoIP provider – Phones are programmed to use dynamic IP addressing – Each network cable to phone needs a ferrite clamp A+ Guide to Managing and Maintaining your PC, 6e 60

Figure 18-70

Use this ATA to turn an analog telephone into an Internet phone A+ Guide to Managing and Maintaining your PC, 6e 61

Supporting Remote Desktop

• Windows XP Professional Remote Desktop – Gives user access to desktop from remote locations – Server must be running Windows XP Professional – Client can run Windows XP Home Ed. or Professional • Accessing a Remote Desktop – Open the Remote Desktop Connection window – Enter address of PC, identification, resources needed • Preparing a Remote Desktop for first use – Configure the computer for static IP addressing – Configure Remote Desktop for service A+ Guide to Managing and Maintaining your PC, 6e 62

Figure 18-75

The desktop of the remote computer is available on your local computer A+ Guide to Managing and Maintaining your PC, 6e 63

Summary

• Internet communication is based on the client/server model • TCP/IP: suite of protocols facilitating transfer of data between client and server • Bandwidth technologies: telephone lines, DSL, cable modem, ISDN, satellite access, wireless access • Internet Connection Sharing (ICS): manages shared Internet connections • Firewall: blocks and filters incoming network traffic A+ Guide to Managing and Maintaining your PC, 6e 64

Summary (continued)

• Router: manages traffic between two networks • Web browser: loads and displays Web pages • E-mail client: used to send and receive e-mail • FTP client: used to transfer files over the Internet • VoIP service: provides voice communications over the Internet A+ Guide to Managing and Maintaining your PC, 6e 65