Yo u might no t see it but its there butterf ingers

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Unformatted text preview: s that attack yo ur P C. At so me Web addresses, the f ile displays co ntent f o r every visito r, and at o thers (like amazo n.co m), a f ile will co ntain pro grams that run o n the Web server to generate custo m co ntent just f o r yo u. Yo u do n’t always type a path o r f ile name as part o f a Web address, but there’s always a f ile lurking behind the scenes. A Web address witho ut a f ile name will lo ad co ntent f ro m a def ault page. Fo r example, when yo u visit “go o gle.co m,” Go o gle auto matically pulls up a page called “index.html,” a f ile that co ntains the Web page that displays the Go o gle lo go , the text entry f ield, the “Go o gle Search” butto n, and so o n. Yo u might no t see it, but it’s there. Butterf ingers, beware! P ath and f ile names are case sensitive—amazo n.co m/ bo o ks is co nsidered to be dif f erent f ro m amazo n.co m/ BOOKS. Mistype yo ur capital letters af ter the do main name and yo u might get a 404 erro r (the very unf riendly Web server erro r co de that means the do cument was no t f o und). IP Addresses and the Domain Name System: “Where Is It? And How Do We Get There?” The IP Address If yo u want to co mmunicate, then yo u need to have a way f o r peo ple to f ind and reach yo u. Ho uses and businesses have street addresses, and telepho nes have pho ne numbers. Every device co nnected to the Internet has an identif ying address, to o —it’s called an IP (Internet pro to co l) address. A device gets its IP address f ro m whichever o rganizatio n is currently co nnecting it to the Internet. Co nnect using a lapto p at yo ur university and yo ur scho o l will assign the lapto p’s IP address. Co nnect at a ho tel, and the ho tel’s Internet service pro vider lends yo ur lapto p an IP address. Lapto ps and o ther end-user machines might get a dif f erent IP address each time they co nnect, but the IP addresses o f servers rarely change. It’s OK if yo u use dif f erent IP addresses during dif f erent o nline sess...
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This document was uploaded on 01/31/2014.

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