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  TCP/IP Key Applications and Application Protocols
           9  TCP/IP Administration and Troubleshooting Utilities and Protocols

Previous Topic/Section
TCP/IP DNS Name Resolution and Information Lookup Utilities (nslookup, host and dig)
Previous Page
Pages in Current Topic/Section
1
23
Next Page
TCP/IP Network Status Utility (netstat)
Next Topic/Section

TCP/IP DNS Registry Database Lookup Utility (whois/nicname)
(Page 1 of 3)

Utilities such as nslookup and host allow an administrator to resolve a DNS domain name to an address and also view detailed information about a domain’s resource records. There are cases, however, where we need to know not the technical information about a domain but rather its DNS registration information. This includes details such as what organization owns the domain, when its registration expires, and who are the designated contacts who manage it.

In the early days of DNS, all domain names were centrally registered by a single authority, called the Internet Network Information Center (InterNIC or just the NIC). To allow Internet users to look up information about domains and contacts, a special server at this center was set up. A protocol was created to allow users to retrieve information from this server, called both nicname and whois. It was initially described in RFC 812 (1982) and then later, RFC 943 (1985). Over time, the name “whois” has become the preferred of the two, and is the one used today for the utility program that allows an administrator to look up DNS registration data. (It can also be used to look up information about IP addresses, but is used for this purpose much less commonly.)

As the Internet grew and expanded, it of course moved away from having a single centralized authority. The modern Internet has a hierarchical structure of authorities that are responsible for registering domain names in different portions of the DNS name space. In recent years, this has been further complicated by the deregulation process that allows multiple registries for the generic top-level domains such as .COM, .NET and .ORG. All of this means that more work is needed to look up domain registration information, since it is distributed across many databases on different servers.

Syntax and Use of the whois Utility

To make it easier for administrators to find information about domains in this large distributed database, modern TCP/IP implementations generally come with an intelligent version of the whois utility. It is able to accept as input the name of a domain and automatically locate the appropriate registry in which that domain’s information is located. The utility is usually used as follows:

whois [-h <whois-host>] <domain>

In this syntax, “<domain>” represents the name about which registration information is requested. The administrator can use the “-h” parameter to force the program to query a particular whois server, but again, this is usually not required. Some implementations also include other options that can be used to direct queries to particular registries.


Previous Topic/Section
TCP/IP DNS Name Resolution and Information Lookup Utilities (nslookup, host and dig)
Previous Page
Pages in Current Topic/Section
1
23
Next Page
TCP/IP Network Status Utility (netstat)
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.