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www, Domain Names, DNS, and IP Addresses
Posted by Bill Venners on May 10, 2000 at 11:03 PM
> Can any body tell me what is the signifiance of "www" in URL.
> For eg. www.artima.com. But some sites don't have this www added
> to their url. for eg. http://java.sun.com
> what is difference between these two urls ?
> Any guidance will be appericiated.
I believe the initial prefix before the first dot allows the
owner of a domain, such as "artima," to get more IP
addresses for their domain name. I've never done this so I don't
know exactly what the procedure is, but I think I know what the
result is. Basically, when you type in a domain such as
www.artima.com, into your web browser's URL field and hit return,
the browser goes to a Domain Name Service (DNS) and looks up
"www.artima.com." What comes back, with luck, is an IP
address that the browser then uses to actually contact the
host that can help it satisfy your request.
Once web sites get big, or have unrelated material, they often
set aside a different IP address for each category, like
mail.yahoo.com or java.sun.com. I assume this helps those web
sites distribute the load coming to their big web site, and
can also serve as mnemonic for users actually typing explicit
URLs into browsers.