How we resolve websites through the use of DNS

Ever wonder how when you type in http://www.google.com/ you end up going to a site with an IP address of 209.85.171.100 (or something similar) ? I never type in an IP address to get to a website, do you? So how does information flow through the system of tubes to get to you? (the internet was never a system of tubes of course http://en.wikipedia.org/wiki/Series_of_tubes) The answer lies in an ingenious system of lookups in the DNS process or Domain Name Service. I'll go through the steps for you so you can get a better grasp of what is going on durring the few seconds from when we press enter and your desired webpage pops up.



For this example we are useing http://www.google.com/ which is broken up as www(web server).google(secondary level domain).com(top level domain).(root level domain)

1. The user types http://www.google.com/ into their favorite browser and presses enter


2. The PC initiates a recursive query to their corprate, home, or ISP DNS server.


3. The DNS server looks at their root hints to find the root zone server and does the first interitive query to it


4. The root zone server sends the information about which top level domain server should be contacted next


5. The DNS server does it's next interitive query to the top level domain server


6. The top level domain server sends information about which second level domain server should be contacted next


7. The DNS sever does it's next interitive query to the second level domain server


8. The second level domain server sends informaiton about where it's web server is located


9. The DNS does it's last interitive query to the web server


10. The web server sends it's IP address to the DNS server


11. The DNS server closes the recursive query after giving the web server IP to the PC


12. The PC goes directly to the web server in question using the direct IP address

Hopefully this article was interesting, but to find out more about DNS servers, zones and lookups feel free to google or if you have a specific question or scenario feel free to leave a comment and I will try to answer you as soon as possible.