ArticlesReader.com Menu
Newest Articles
Most Viewed Articles
ArticlesReader.com RSS
Submit Article
Login
Signup
Search the articles

Articles Main Categories
Advice
Animals
Automobiles
Business
Career
Communications
Computer Programming
Computers
Entertainment
Environment
Family
Fashion
Finance
Food
Health & Medical
Home & Garden
Humor
Internet Business
Internet Marketing
Legal
Leisure & Recreation
Marketing
Other
Politics
Reference & Education
Religion
Self Improvement
Sports
Technology & Science
Travel
Writing
Subscribe
Receive alert message from us when new articles submitted to our site for free.

Enter your name

Enter your email

Syndicate

















Related Products
Home::Computers

DNS

Author : Richard Lowe
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 TCP/IP address - but some real magic is
occurring under the covers of the internet.

You see, the internet uses a special number known as a TCP/IP
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, 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), 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 TCP/IP has been
designed to attempt to reduce the expense (the time) it takes to
translate a name to a TCP/IP 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, 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 TCP/IP 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, 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, 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, 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.

Once the name server who knows the address of "internet-tips" is
found, it will be asked if it knows the address of the "www". It
will either return the address (this is very likely) or return
the name(s) of name servers that might know the answer themselves.

Now that the name server (primary or secondary) as the actual
TCP/IP address it sends it back to your machine.

I hope that helps explain, just a little, how the magic really
works under the covers.


About the Author

Richard Lowe Jr. is the webmaster of Internet Tips And Secrets
at http://www.internet-tips.net - Visit our website any time to
read over 1,000 complete FREE articles about how to improve your
internet profits, enjoyment and knowledge.

Spam emails More free articles

Related articles


  1. Power Leveling: Bots, Wardens, Suspensions, and Bans.
  2. Wow Gold: Power Leveling Variety of Services
  3. The World behind Power Leveling: The Power Leveling Industry
  4. Wow Gold: Choosing Safe Power Leveling Companies
  5. Tech Buzz Today! A Look Inside The Mind Of Pop Culture And The Internet
  6. Printing a Panorama at Home
  7. What You Need To Break Into The Billboard Market
  8. Net-centric Data Storage Using Marine Robotic Equipment
  9. Robots to Replace Obnoxious Rent-A-Cops
  10. The Tech Heads Need To Make It Simple For the Average Human
  11. CDC, FDA, 4D Holographic Data Imaging of Flows
  12. Professional Help with Your Computer May Be Cheaper Than You Think
  13. Locating The Perfect Laptop Computer
  14. Extend The Life Of Your Laptop Battery
  15. Battery Sizes And Types
  16. Cleaning and Organizing Your Computer
  17. Computer Aided Drafting
  18. Information/Human Age: Bringing Family and Friends Closer Together
  19. Preparing for a Career in Information Technology
  20. Getting Started In Information Technology Computer Consulting
  21. Internet Security Basics 101
  22. The Evolution of Technology - The History of Computers
  23. The Language of Color
  24. Do You Read On The Train?
  25. Network Monitoring for Serious eCommerce
More related feeds
Kaminsky on the net-shaking DNS bug
Wired's Danger Room has a good interview with Dan Kaminsky, whose DNS hack has been burning up the wires. Dan figured out a means of disrupting the entire Internet by poisoning DNS. The exploit's existence and scope have been hotly ...

Details of DNS Flaw Leaked; Exploit Expected by End of Today
Despite Dan Kaminsky's efforts to keep a lid on the details of the critical DNS vulnerability he found, someone at the security firm Matasano leaked the information on its blog yesterday, then quickly pulled the post down. ...

DNS Exploit in the Wild
Well it took a little longer than expected so it's not quite a zero-day exploit, but the anticipated attack code to exploit the critical Kaminsky DNS cache-poisoning flaw is now in the wild (assuming there wasn't one already out there). ...

Attack Code Published For DNS Vulnerability
ZDNet is reporting that HD Moore has released exploit code for Dan Kaminsky's DNS cache poisioning vulnerability into the point-and-click Metasploit attack tool. From the article: 'This exploit caches a single malicious host entry into ...

Kaminsky on How He Discovered DNS Flaw and More
Dan Kaminsky is understandably swamped today, given the unexpected early release of information about the critical DNS flaw he discovered that potentially affects the security of every web site on the internet. ...

DNS exploit in the wild
We've been tracking Metasploit commits since Matasano's premature publication of [Dan Kaminsky]'s DNS cache poisoning flaw on Monday knowing full well that a functional exploit would be coming soon. Only two hours ago [HD Moore] and ...

Have You Updated Your DNS Settings?
Recently, a significant threat to DNS, the system that translates names you can remember (such as www.doxpara.com) to numbers the Internet can route (66.240.226.139) was discovered, that would allow malicious people to impersonate ...

The DNS Debacle In Poetic Review
It was with DNS, It was nasty and raw. He decided than rather to disclose all at once he'd instead only tell people who'd fix it in months. So some meetings were had and work soon began vendors wrote patches coordinated by Dan ...

Is Your DNS Server Safe? Major Security Hole Needs To Be Patched ...
Dan Kaminsky found a security hole in DNS recently, the details of which he was keeping quiet so providers could fix and release patches and DNS server owners could get those patches deployed, in order to avoid security breaches on the ...

Aussies play down DNS disaster
One large Australian organisation and a local computer security advisor have played down the importance of a security flaw in the global Domain Name System (DNS) that has led to panic in some security circles around the globe.

 


 

© 2007 articlesreader.com - All Rights Reserved