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13.1. What DNS Does

As you've read earlier, a DNS server's main job is "name resolution," which means that you can ask a DNS server, "what IP address does the machine named www.minasi.com have?" That's important because computers don't care about names like www.minasi.com; they care about IP addresses like 70.165.73.5. The beauty of DNS, then, is that you can visit my Web site by firing up a copy of Internet Explorer and typing www.minasi.com into the address bar and then Internet Explorer asks a DNS server to resolve the name to an IP address. Once IE has got the IP address, it can take you to my Web site.

NOTE

By the way, my cable provider, Cox Communications, makes me pay considerably extra for a static — unchanging — IP address for my Web server, but they like to force me to change that IP address about every nine months (and if you're wondering exactly how that's "static," then don't ask me, I have no idea either), so if you try resolving www.minasi.com using the tools I'll show you later in this chapter, don't be surprised if your DNS server tells you a different IP address than 70.165.73.5. That's actually another neat thing about name resolution: it disconnects my Web site's name from its IP address. I've run a Web server with that name since about 1995, and over that time I've gotten my IP addresses from four different providers. None of my visitors were bothered by the changes, however, thanks to DNS. My business is associated with an online name, not an IP address, so I'm free to move my online presence to any ISP that I wish. Unlike Patrick McGoohan's character in the old TV series The Prisoner, I am a name — not number! — and DNS makes that possible.


  

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