Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide


NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

Read offline with no ads or diagram watermarks!
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  Name Systems and TCP/IP Name Registration and Name Resolution
           9  TCP/IP Name Systems: Host Tables and Domain Name System (DNS)
                9  TCP/IP Domain Name System (DNS)
                     9  DNS Name Servers and Name Resolution
                          9  DNS Resolution Concepts and Resolver Operations

Previous Topic/Section
DNS Resolution Concepts and Resolver Operations
Previous Page
Pages in Current Topic/Section
1
2
Next Page
DNS Basic Name Resolution Techniques: Iterative and Recursive Resolution
Next Topic/Section

DNS Resolver Functions and General Operation
(Page 1 of 2)

The DNS name servers we explored in the preceding section are arguably the most important part of the system as a whole. After all, they store all the data on the system and actually provide the addresses we need when names are given to them; without these servers, there would be no DNS at all. Of course, what use is a server if nobody is asking for service? The clients in the system, called resolvers, are also important, because they initiate the process of name resolution; resolvers are where the “rubber meets the road”, so to speak.

The operation of DNS resolvers is explained in the two main DNS standards. RFC 1034 describes the functions performed by resolvers, and how they work in general terms. This includes a discussion of the algorithm used to conduct name resolution. RFC 1035 deals more with the implementation details of resolvers, and the fine points of how they do their jobs. Several subsequent standards have of course modified these base standards, changing some of the ways that resolvers work in different ways.

Name Resolution Services

Just as the main job of a DNS server is to store DNS name data and “serve” it when it receives requests, the main job of a DNS resolver is to, well, resolve. J While most people only think of name resolution as the process of transforming a DNS name into an IP address, this is but one of several types of resolution services performed by DNS. A few of the most typical types of DNS resolution are:

  • Standard Name Resolution: Taking a DNS name as input and determining its corresponding IP address.

  • Reverse Name Resolution: Taking an IP address and determining what name is associated with it.

  • Electronic Mail Resolution: Determining where to send electronic mail (e-mail) messages based on the e-mail address used in a message.

There are other types of resolution activities as well, though again, most name resolution requests are of the “standard” variety, making it the primary focus in our discussion.


Previous Topic/Section
DNS Resolution Concepts and Resolver Operations
Previous Page
Pages in Current Topic/Section
1
2
Next Page
DNS Basic Name Resolution Techniques: Iterative and Recursive Resolution
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005

© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.