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!

Enjoy The TCP/IP Guide? Get the complete PDF!
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  TCP/IP Key Applications and Application Protocols
           9  TCP/IP Administration and Troubleshooting Utilities and Protocols

Previous Topic/Section
TCP/IP Address Resolution Protocol Utility (arp)
Previous Page
Pages in Current Topic/Section
1
2345
Next Page
TCP/IP DNS Registry Database Lookup Utility (whois/nicname)
Next Topic/Section

TCP/IP DNS Name Resolution and Information Lookup Utilities (nslookup, host and dig)
(Page 1 of 5)

The Domain Name System (DNS) is a critically important part of TCP/IP internetworks, especially the modern Internet, because it allows hosts to be accessed using easily-remembered names rather than confusing numerical addresses. Two different primary types of devices are involved in the operation of DNS: DNS name servers that store information about domains, and DNS resolvers that query DNS servers to transform names into addresses, as well as performing other necessary functions.

DNS resolvers are employed by Internet users on a continual basis to translate DNS names into address, but under normal circumstances, they are always invoked indirectly. Each time a user types a DNS name into a program such as a World Wide Web browser or FTP client —or even uses it in one of the other utilities in this section, such as ping or traceroute—the resolver automatically performs the name resolution without the user having to ask. For this reason, there is no need for users to manually resolve DNS names into addresses.

However, administrators often do need to perform a DNS resolution manually. For example, when troubleshooting a problem, the administrator may know a host’s name but not its address; in the case of a security problem, the address may show up in a log file but the host name may not be known. In addition, even though users do not need to know the specifics of the resource records that define a DNS domain, administrators often need to be able to check these details, to make sure a domain is set up properly. Finally, admins also need some way to be able to diagnose problems with DNS servers themselves.


Previous Topic/Section
TCP/IP Address Resolution Protocol Utility (arp)
Previous Page
Pages in Current Topic/Section
1
2345
Next Page
TCP/IP DNS Registry Database Lookup Utility (whois/nicname)
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.