Testing a DNS Server


The first thing to consider is the client operating system from which the testing will be orchestrated. Windows generally does not make the top of the list in this regard. The use of a *unix* variant, Linux or (FreeBSD) is *very* highly recommended. These operating systems were designed from the ground up to be networked operating systems. As a result, a plethora of tools is readily available, even in minimal OS configurations, to perform network related tasks and test procedures. My personal favorite is FreeBSD, and in fact this document is being prepared on my FreeBSD 7.0 desktop.

The DIG utility is provided with BIND¹ (currently the DNS server that runs most of the internet)

However; most *nix type operating systems have it included in one of the standard binary directories, even if BIND is not installed. Get to know DIG, as it will be your best friend in the DNS world. The following list of commands should give the reader some idea about it's capabilities:







dig @66.233.116.31 mx fourcalorieservers.com ---- This command displays the mail exchange server info for the fourcalorieservers.com domain as presented by the DNS server. The "66.233.116.31" dotted decimal octet is the address of the DNS server being queried.


dig @66.233.116.31 ns fourcalorieservers.com ---- This command displays the name server info for the fourcalorieservers.com domain as presented by the DNS server. The "66.233.116.31" dotted decimal octet is the address of the DNS server being queried.


dig @66.233.116.31 fourcalorieservers.com ---- This command displays the DNS address record for the naked (or root) domain name (fourcalorieservers.com)


dig @66.233.116.31 -x 209.40.199.130 ---- This command displays the reverse (PTR) record for the address 209.40.199.130


dig @66.233.166.31 a fourcalorieservers.com ---- This command displays the dns "address" record for the naked domain name (and is the equivalent of the previously shown naked domain address query command. The "address" record is the default query type for DiG, when no explicit query type is given. This is also true of the older nslookup utility. The nslookup utility is available on Windows, and is used within a command shell (Start menu / run / command).


dig @66.233.116.31 a www.fourcalorieservers.com ---- This command displays the dns "address" record for the world wide web server at the fourcalorieservers.com domain. Note that there is nothing magical about the "www" domain name. It is the www server only if the domain operator intends it to be, and is usually assigned, by tradition/fiat to be the www server (In web guru parlance called the http server).


dig @66.233.116.31 a mail.fourcalorieservers.com ---- This command displays the dns "address" record for the mail server at the fourcalorieservers.com domain. Note that there is nothing magical about the "mail" domain name. It is the mail server only if the domain operator intends it to be, and is usually assigned, by tradition/fiat to be the mail server (In internet guru parlance called the smtp server. Note also that the mail server domain name is usually retrieved, as a first step, using the mx command).


DiG has many other query capabilities, but I have expressed command syntax for the ones that are most directly applicable to the little Four Calorie DNS server. Read the Dig manual for more information.






** The nslookup Utility

Note that we mentioned nslookup. It is officially deprecated, and in the future may not be available. However; since it is one of the only tools natively available to users of Windows, some explanation is a good thing:


Start nslookup with a command shell in Windows, by typing nslookup. The nslookup prompt should appear. Then set the desired DNS server to use in subsequent query operations, by typing "Server 66.233.116.31" and pressing the enter key. Note that the given address is for fourcalorieservers.com, and hey, you may use it if you like. :-) Note that a domain name for the server may be used if your system configuration has a pointer to a public DNS server.

Type the domain name that you would like to resolve to an address. Type www.fourcalorieservers.com, for instance. A dotted decimal address should be shown.



¹ Bind (Berkley Internet Name Daemon) is maintained by the Internet Software Consortium (not affiliated with this site)


- Datazygte, Inc, contact: ronscheckelhoff@fourcalorieservers.com