DNS help

[Charles Lee]

Jason Clinton wrote:

> Hello everyone. I know I should have learned this long ago but somehow 
> it never seemed relevant to anything I was working on.
>
> Can someone point me to a quick reference or quickly summarize how 
> those silly little flags in DNS affect resolve IP addresses? Was is 
> MX? A? How does www work?
>
> I know this all releates to bind and the like. I've been using dig and 
> host to do my DNS lookups lately but only partially understand the 
> output. Maybe someone could reply with a generic dig output and 
> explain what each field means?
>
> Thank you!
>
A = Address Record
This record points a host name to an IP address.   This type of record 
defines the canonical name of a host. (HOST.domain.com -> 192.168.0.1)

CNAME = Canonical Name Record
This creates an alias of a canonical name. (ALIAS.domain.com -> 
HOST.domain.com)

MX = Mail Exchanger Record
This tells the world where to send mail for your domain. 
(SMTPSERVER.isp.net)

PTR = Pointer Record
This allows you to point an IP address to a canonical name.  The syntax 
is kind of odd with the IP address listed backwards and .IN-ADDR.ARPA 
tacked on the end. (1.0.168.192.IN-ADDR.ARPA -> HOST.domain.com)

The above are the most common types of DNS records you'll deal with.  
There are more.  Some are depracated, others just aren't used all that 
often.

http://www.ietf.org/rfc/rfc1035.txt

--
Charles Lee