> Date: Fri, 23 Oct 2009 08:30:08 -0400
> From: dave.l...@pixelhammer.com
> To: freebsd-questions@freebsd.org
> Subject: DNS Question
> Good morning.
> I have been asked by my co-workers and sales why I always create a A 
> record for new domains we host instead of a CNAME.
> The issue I run into lately with some domains is that a client has a 
> website with a industry host such as frank.relator.com and he wants to 
> have DNS point www.frank.com to frank.relator.com with a CNAME. The 
> client does not want an A record for frank.com.
> Somewhere, in a class far far away, I was taught a DNS zone had to have 
> a A record to function properly. I can't seem to locate anything in the 
> RFCs.
> Am I wrong?

I think you are confusing basics of DNS records. you are partially correct in 
that a DNS zone needs an initial A record to be able to translate a name to an 
IP, but there is nothing wrong about setting up a CNAME to point to a record in 
a different zone instead. you just cannot do a zone that has a CNAME only that 
does not at some point to a valid A record. CNAMEs are forwarders only whereas 
A records are actual lookups.
for proper way to set this up....
The A record would be assigned for the main name that you want to associate to 
an IP address.
The CNAME record just relates a different name to that original name. this 
allows you to change the IP address of the server and only have to update the 
original A record instead of every DNS record for that server.
for small number of vhosts, this would not really be an issue, but imagine if 
you were hosting a couple hundred vhosts from a single IP and then had to 
change that IP because you switched your ISP. It would take you a LONG time to 
update them if they were all A records, but only a couple of seconds if you had 
it properly set up as CNAME's
www.bobshosting.com    A
www.vhost1.com          CNAME  www.bobshosting.com.
www.vhost2.com          CNAME  www.bobshosting.com.
www.vhost3.com          CNAME  www.bobshosting.com.
www.vhost4.com          CNAME  www.bobshosting.com.


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