Does "@" in CNAME record not work?

[Mark.Andrews at nominum.com]

> 
> 
> 
> Cricket Liu wrote:
> > 
> > > >         mydomain.com            SOA ...
> > > >         mydomain.com            NS ns1.mydomain.com
> > > >         mydomain.com            A 192.168.0.4  ; must be an A record
> > > >         ns1.mydomain.com        A 192.168.0.4  ; must be an A record
> > > >         www.mydomain.com        CNAME mydomain.com
> > >
> > > Doesn't that bring me back to the problem pointed out in the Bind/DNS
> > > book (3rd edition, pgs. 64-65)?
> > 
> > Why is that a problem?  Why would you want mail addressed
> > to user at mydomain.com to canonicalize to user at www.mydomain.com?
> > Having mail addressed to user at www.mydomain.com canonicalize to
> > user at mydomain.com makes some sense, though.
> > 
> > cricket
> 
> 
> Mark, Cricket, et al,
> 
> Let me explain my situation a bit...
> 
> As I indicated in my earlier, I'm a real newbie, and just starting to
> learn about DNS and Bind.
> 
> After struggling with setting Bind up, I finally got a copy of the book
> :), and started trying to set my Bind files "correctly" (whatever that
> means).
> 
> Actually, earlier in my experimentation, I had everything working, but
> without using aliases (i.e., using all IP addresses).  
> 
> Then, as I read the book, I ran across the section that I cited above,
> which I took (and which I guess I still take) to imply that, in a
> "correct" DBxxx.. file, you should TRY to avoid having names with the
> same IP address.  I've read those two paragraphs (bottom of pg. 64, top
> of pg. 65) over several times, and I THINK that's what it's trying to
> say?
> 
> Now, given that information, I started staring at my DBxxx.. file,
> trying to figure out how I could configure the file in such a way that I
> did not use the specific IP address for mydomain.com 192.168.0.4 (since
> ns1.mydomain.com was also 192.168.0.4).
> 
> My first thought (remember, I'm new at this) was "Oh, that's easy, I'll
> just use a CNAME record with either "mydomain.com." or "@", but as
> others have amply explained, that's not allowed.
> 
> Perhaps this is more of a "theoretical exercise".  But, what I seem to
> have ended up with seems like somewhat of a conundrum, i.e., that if
> mydomain.com and ns1.mydomain.com both happen to have the same IP
> address, and if I'm to configure a "completely correct" DBxxx.. file (at
> least according to the book), there is no way to do this?
> 
> I hope that this is all clear?
> 
> Thanks in advance,
> Jim
> 

	Whether to use CNAMES or A records is a matter of personal
	preference provided you don't use CNAMES where they are
	not allowed.

	Using CNAMES does not make you "completely correct" just
	as not using CNAMES does not make you "completely correct".

	You use CNAMES where you want one name to be an ALIAS for
	another.  You want that name to inherit all the other record
	not just A records.

	Mark

--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com