DNS Internet Articles | February 16 Jake Bailey Patriots Jersey , 2002 When you enter a web site address (a URL) into your ... bar (or click on a ... you actually set in motiona complex series of events. It sounds simple - the name must ...
When you enter a web site address (a URL) into your browser's address bar (or click on a hyperlink), you actually set in motion a complex series of events. It sounds simple - the name must be translated into a TCPIP address - but some real magic is occurring under the covers of the internet.
You see, the internet uses a special number known as a TCPIP address to identify machines. Each and every machine on the internet has one of these numbers. An example is 23.5.67.9 - each of the four numbers is called an octet. Thus, the URL www.internet-tips.net might actually translate to 23.5.67.9 using something called DNS.
Okay Hjalte Froholdt Patriots Jersey , before I go on any further with this explanation, understand this article is a highly simplified description of a process that is actually highly technical, extremely complex and very difficult for even the experts to totally understand. People spend years in training learning how this all works.
When your machine needs to retrieve a URL (when you enter a web site address in the browser address line, for example) Yodny Cajuste Patriots Jersey , it first checks to see if it already knows how to translate the address. Depending upon the operating system and browser, a number of different steps might take place.
The first basic fact to understand is that TCPIP has been designed to attempt to reduce the expense (the time) it takes to translate a name to a TCPIP number. This translation is potentially extremely time consuming, and users don't like to wait. So a number of intermediate steps have been added to attempt to speed things up.
First your system looks to see if it already has done the translation recently (this is called caching). What happens is each time your computer successfully performs a translate it makes a note of the results off to the side. Later, if you enter the same URL Damien Harris Patriots Jersey , the system looks on it's list, finds it already has the address and returns that value.
If your system has not translated the URL before, it might check the LMHOSTS or HOSTS files (these are just text files used to aid in translating host names to TCPIP addresses) and perhaps other things as well. Note that if the address has been cached, it might be refreshed (retrieved from the internet again) if it is too old (perhaps the address was translated a few days ago). The HOSTS and LMHOSTS files are never refreshed - they are assumed to be correct.
Now the system has no choice except to look outside to the internet to try and translate the URL. So your system will send a translation request out to your primary DNS server. This is usually supplied to you by your ISP when you installed your computer on the internet. If the primary DNS server cannot be reached for some reason Chase Winovich Patriots Jersey , then the secondary DNS server will be queried.
Okay, now it gets a little more complicated so we will work with an example. Assume the address "www.internet-tips.net". A name server may or may not (depending upon what type of name server and how it is configured) remember addresses that have been requested before. If they remember, then they will simply return the translation directly back to your computer.
Most likely, though Joejuan Williams Patriots Jersey , the primary DNS does not know how to translate the hostname, so it will go out and ask some other name servers. It will start with the root domain (.NET in our example) and ask it if it knows how to translate "internet-tips". The .NET name server may or may not know. So it will either say "sure, here's the address" or "no, I don't know N'Keal Harry Patriots Jersey , but here are the addresses of some other name servers in .NET that may know." These servers will be asked, and will perform the same actions. This will continue until there is no where to turn for the answer (there is no resolution) or the translation is found.