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Practical PC, 7th Edition Chapter 7: Connecting to the Internet Connecting to the Internet • FAQs: – – – – – How does the Internet work? What should I know about Internet service? What are my options for Internet service? How do local area networks offer Internet access? How do I connect to the Internet from a local area network? – How does firewall software protect my computer from intrusions? – How does encryption protect my computer from intrusions? • Technology: TCP/IP Practical PC, 7th Edition 2 How does the Internet work? • The Internet is a global network of computers – Connects millions of smaller networks, computers, and other devices – Not owned or operated by any single corporation or government – Maintained by network service providers (NSPs) • • • • AT&T British Telecom Sprint Verizon Practical PC, 7th Edition 3 How does the Internet work? – NSP equipment and links are tied together by network access points (NAPs) • NAPS supply Internet connections to Internet service providers such as EarthLink, AOL, and Comcast – An Internet service provider is a company that offers Internet access to individuals, businesses, and smaller ISPs – Data is exchanged using TCP/IP, which is a protocol that divides information into packets of data • Packets are sent to their destinations through routers Practical PC, 7th Edition 4 How does the Internet work? – Every device connected to the Internet has a unique IP address • It is a long string of numbers • To make it easier for users, many Internet servers also have an easy-to-remember name, i.e., nike.com • The official term for this name is a fully qualified domain name (FQDN) but most people just call it a domain name Practical PC, 7th Edition 5 How does the Internet work? – Domain names end with an extension that indicates its classification Figure 7-1 Practical PC, 7th Edition 6 What should I know about Internet service? • Internet services vary in cost, speed, and reliability • Capacity of an Internet connection is referred to as bandwidth – Measured in bits per second – Range from 56 Kbps (56,000 bits per second) to 100 Mbps (100 million bits per second) or more Practical PC, 7th Edition 7 What should I know about Internet service? • Connection speed tells how fast data travels – Measured in milliseconds (ms) – Lower numbers indicate faster speeds • Best for playing online games, using voice over IP, watching online videos, and participating in Web conferences • Symmetrical connections – Data travels upstream from your computer to the Internet at the same speed as it travels downstream from the Internet to your computer Practical PC, 7th Edition 8 What should I know about Internet service? • Asymmetrical connections – More common – Data travels faster downstream than upstream – Downstream speed is important because most users have more information coming to their computers than going from their computers Practical PC, 7th Edition 9 What are my options for Internet service? • Cable Internet service – Uses same infrastructure as cable television – Offers fastest access speeds – Uses a cable modem – Usually offered in a monthly subscription • DSL (digital subscriber line) – Broadband that runs over standard phone lines – Offers fast, affordable connections – Can be symmetrical or asymmetrical Practical PC, 7th Edition 10 What are my options for Internet service? • Dial-up Internet service – Uses a voiceband modem and telephone lines – Typically less than $10/month – Access speed is slow – Not suitable for playing games or watching videos • Satellite Internet service – Distributes asymmetric access via a personal satellite dish – In rural areas may be only choice other than dialup – Susceptible to bad weather and slow signal time Practical PC, 7th Edition 11 What are my options for Internet service? • WiMax – One of the newest technologies – Limited availability – Transmits data to nearby communication tower • Mobile broadband – Access is through high-speed cellular technology, referred to as 3G and 4G – Used for smartphones, laptops, notebooks, tablets, and netbooks – Can have slower speeds, dropped connections Practical PC, 7th Edition 12 How do local area networks offer Internet access? • Local area networks (LANs) connect computers in a very small geographical area, most often within the same building • LAN’s router is connected to cable Internet or DSL and passes Internet access to computers connected to the LAN – Ethernet • Fast and secure wired network technology • Popular with businesses, school computer labs and home networks Practical PC, 7th Edition 13 How do local area networks offer Internet access? – Wi-Fi (or WiFi) • • • • Popular wireless technology Transmits data using radio waves Slower and less secure than Ethernet WiFi hotspot is a wireless network used by coffee shops, hospitals, airports, libraries, and school campuses to provide access to guests using laptop computers or mobile devices Practical PC, 7th Edition 14 How do local area networks offer Internet access? • To access the Internet using a local area network, connect to the LAN – Windows automatically senses nearby networks and displays their SSIDs – Some networks are secured; others are open to the public • To connect to a secure network, a correct encryption key must be entered Practical PC, 7th Edition 15 How do local area networks offer Internet access? Practical PC, 7th Edition 16 How do local area networks offer Internet access? Figure 7-6 Practical PC, 7th Edition 17 Hardware: Wired and wireless network devices Practical 18 PC 6th Edition How does firewall software protect my computer from intrusions? • An intrusion is any access to data or programs by hackers, criminals, or other unauthorized persons • Access can be gained through an open port – A port is any pathway of data in or out of a computer – Port scanning software looks for unprotected computers and can attack an unprotected computer within four minutes Practical PC, 7th Edition 19 How does firewall software protect my computer from intrusions? • Firewall software – Makes sure incoming information was actually requested and is not an unauthorized intrusion – Blocks activity from suspicious Internet addresses – Reports intrusion attempts – Essential for computers connected directly to the Internet • Windows system includes Windows Firewall • Only one firewall should be active at any given time Practical PC, 7th Edition 20 How does firewall software protect my computer from intrusions? Practical PC, 7th Edition 21 How does encryption protect my network from intrusions? • Wireless signals can be picked up by any device within the network coverage area, including hackers – WEP was the original wireless encryption • Provides level of confidentiality similar to that of a wired network • Very easy to bypass • Does protect from casual hacks and inadvertent cross talk from nearby networks Practical PC, 7th Edition 22 How does encryption protect my network from intrusions? – Newest versions of encryption make sure that packets have not been intercepted or tampered with in any way • WPA and WPA2 • PSK – Encryption keys are created when wireless encryption is set up • Anyone wishing to join the network must key in the encryption key Practical PC, 7th Edition 23 How does encryption protect my network from intrusions? Practical PC, 7th Edition 24 Technology: TCP/IP • TCP/IP – Primary protocol suite responsible for message transmission on the Internet – Protocol suite • Combination of protocols that work together – TCP breaks a message or file into packets – IP is responsible for addressing packets so they can be routed to their destination – TCP/IP is public, free, extensible, and easy to implement Practical PC, 7th Edition 25 Technology: TCP/IP • Circuit switching – Used by early communications networks – Established dedicated links between two communicating parties, i.e., establishing a private link between two telephone lines – Practically, it is inefficient • Packet switching – Divides messages into several packets – Packets can be routed independently – More efficient than circuit switching Practical PC, 7th Edition 26 Technology: TCP/IP Practical PC, 7th Edition 27 Technology: TCP/IP • IP addresses – Originated on Internet as part of the TCP/IP protocol – Used to uniquely identify computers on the Internet and on LANs – Two kinds • IPv4 – addresses are divided by periods into four segments • IPv6 – numbers are divided by periods into eight segments Practical PC, 7th Edition 28 Technology: TCP/IP – When connected to the Internet through a router or LAN, the IP address of the computer can be different from the address used for the Internet connection • Shields computer from intrusion attempts Practical PC, 7th Edition 29 Technology: TCP/IP Practical PC, 7th Edition 30 What is an IP address? Practical 31 PC 6th Edition