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
1234
5
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 5 of 5)

The dig Utility

The second alternate to nslookup is dig, which stands for “Domain Information Groper” (likely a play on the supposed origin of the name “ping”). It differs from the host command in that it provides considerably more information about a domain, even when invoked in the simplest of ways. It is also quite a bit more complicated, with a large number of options, and features such as a batch mode for obtaining information about many domains.

The basic syntax for the dig command is different from nslookup or host, because if a non-default name server is specified, it is prepended with an at sign (“@”) and comes before the host to be looked up. A specific type of resource record can also be specified, like this:

dig [@<server>] <host> [<type>]

Table 294 shows the output from running dig on the same domain (www.pcguide.com) that I used as an example for nslookup and host. You can see that it provides much more information about the domain.


Table 294: DNS Name Resolution Using the dig Utility

%dig www.pcguide.com
; <<>> DiG 9.2.1 <<>> www.pcguide.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 15912
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 0

;; QUESTION SECTION:
;www.pcguide.com. IN A

;; ANSWER SECTION:
www.pcguide.com. 3600 IN CNAME pcguide.com.
pcguide.com. 3600 IN A 209.68.14.80

;; AUTHORITY SECTION:
pcguide.com. 3600 IN NS ns0.ns0.com.
pcguide.com. 3600 IN NS ns23.pair.com.

;; Query time: 1840 msec
;; SERVER: 209.68.1.87#53(209.68.1.87)
;; WHEN: Tue Nov 18 16:05:08 2003
;; MSG SIZE rcvd: 109Server: ns1-mar.starband.com


The dig command also allows specific types of resource records to be looked up, and includes dozens of options and settings. Since this topic is already getting very long and dig is by far the most advanced of the three utilities, I will stop here; consult your system’s documentation for the full instructions on how dig works and a list of its parameters.

Key Concept: Most TCP/IP implementations provide one or more utilities that can be employed by an administrator to manually resolve DNS domain names to IP addresses or perform related searches for DNS information. One of the most common is nslookup, which allows a host name to be translated to an address or vice-versa; it has both interactive and non-interactive modes. On some operating systems, nslookup has been replaced by the host utility for simple DNS lookups, and the dig program for more detailed inspections of DNS resource information.


On The Web: The dig utility is very useful, but has still not been implemented on some systems. Fortunately, there is an online dig utility you can access using your browser on the Internet. Find it at http://www.gont.com.ar/tools/dig.



Previous Topic/Section
TCP/IP Address Resolution Protocol Utility (arp)
Previous Page
Pages in Current Topic/Section
1234
5
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.