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  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 Messaging and Message, Resource Record and Master File Formats

Previous Topic/Section
DNS Name Notation and Message Compression Technique
Previous Page
Pages in Current Topic/Section
123
4
Next Page
DNS Changes To Support IP Version 6
Next Topic/Section

DNS Master File Format
(Page 4 of 4)

Specific Resource Record Syntax and Examples

Table 179 shows the specific formats and examples for each of the common resource record types. The fields are basically the same as the ones explained in the DNS binary record formats. I have included explanatory “comments” using the DNS comment format. Assume that the examples in this table are for the zone “googleplex.edu”:


Table 179: DNS Master File Format Syntax and Examples

Resource Record Text Code

Resource Record Type

Resource Record Format / Example

A

Address

<domain-name> [<ttl>] IN A <ip-address>

admin1.googleplex.edu IN A 204.13.100.3 ; A FQDN.
admin2 IN A 204.13.100.44 ; A PQDN equivalent to
; admin2.googleplex.edu

NS

Name Server

<domain-name> [<ttl>] IN NS <name-server-name>

googleplex.edu. IN NS custns.bigisp.net ; Secondary NS

CNAME

Canonical Name

<domain-name> [<ttl>] IN CNAME <canonical-name>

www IN CNAME bigserver ; www.googleplex.edu is really
; bigserver.googleplex.edu.

SOA

Start Of Authority

<domain-name> [<ttl>] IN SOA <m-name> <r-name> (
<serial-number>
<refresh-interval>
<retry-interval>
<expire-interval>
<default-ttl>)

googleplex.edu. IN SOA ns1.googleplex.edu it.googleplex.edu (
42 ; Version 42 of the zone.
21600 ; Refresh every 6 hours.
3600 ; Retry every hour.
604800 ; Expire after one week.
86400) ; Negative Cache TTL is one day.

PTR

Pointer

<reverse-domain-name> [<ttl>] IN PTR <domain-name>

3.100.13.204.IN-ADDR.ARPA. IN PTR admin1.googleplex.edu.

MX

Mail Exchange

<domain-name> [<ttl>] IN MX <preference-value> <exchange-name>

googleplex.edu. IN MX 10 mainmail.googleplex.edu.
IN MX 20 backupmail.googleplex.edu

TXT

Text

<domain-name> [<ttl>] IN TXT <text-information>

googleplex.edu. IN TXT "Contact Joe at X321 for more info."


Note that the PTR record would actually be in the IN-ADDR.ARPA domain, of course.

Table 180 contains a “real-world” example of a DNS master file, taken from my own “pcguide.com” server (slightly modified), hosted by (and DNS information provided by) the fine folks at pair.com. Note the use of “@” as a short-cut to mean “this domain” (“pcguide.com”):


Table 180: Sample DNS Master File

$ORIGIN pcguide.com.
@ IN SOA ns23.pair.com. root.pair.com. (
2001072300 ; Serial
3600 ; Refresh
300 ; Retry
604800 ; Expire
3600 ) ; Minimum

@ IN NS ns23.pair.com.
@ IN NS ns0.ns0.com.

localhost IN A 127.0.0.1
@ IN A 209.68.14.80
IN MX 50 qs939.pair.com.

www IN CNAME @
ftp IN CNAME @
mail IN CNAME @
relay IN CNAME relay.pair.com.


 


Previous Topic/Section
DNS Name Notation and Message Compression Technique
Previous Page
Pages in Current Topic/Section
123
4
Next Page
DNS Changes To Support IP Version 6
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.